Table of Contents
Chapter 1: Understanding rigid boxes
1.1 What is a rigid box?
A rigid box is a type of high-end packaging known for its exquisite appearance, refined craftsmanship, and intricate structure. It is named for the multiple pasting processes involved in its production. Essentially, pasting involves adhering the box’s surface paper to an industrial board.
Rigid boxes are renowned for their robust and durable construction, maintaining their shape and integrity even under pressure. They find wide application across various industries, including luxury goods, cosmetics, electronics, jewelry, and gift packaging. These boxes are favored for their ability to convey quality and elegance, making them an ideal choice for high-end products.
1.2 What are the materials of rigid boxes?
1.2.1 Gray board paper
Gray board paper, also known as greyboard, is a type of paperboard made from recycled waste paper and is considered an environmentally friendly packaging material. It comes in three main types: single gray, double gray, and full gray. Single gray board has one side that is gray; full gray board is uniformly gray on both sides, including the core; double gray board has gray on both sides, with a yellowish core visible from the cut edge. While double gray and full gray may look similar externally, full gray board tends to have better rigidity. Double gray board is more cost-effective, hence its widespread use in rigid box applications.
Gray board paper requires a smooth surface without obvious bumps, curls, black spots, crushing marks, delamination, damage, bubbles, etc. The entire sheet should be flat, without distortion or waves. Its color should be uniform, meeting standards for smoothness, flexibility, tensile strength, smoothness, and cleanliness.
Here’s a brief overview of the six major parameters for gray board paper:
Size and dimensions: For double gray board, size is a quality standard indicator, with allowable size deviations not exceeding ±3mm. The way dimensions are written is also important, as paper often has grain direction parallel to the second dimension.
Basis weight: This refers to the weight of paper per square meter. For double gray, single gray, and composite gray board, the allowable basis weight deviation is typically between +3% to -5%. Products outside this range are considered non-compliant.
Ply bond strength: This measures the strength of the bond between wet paperboard layers when subjected to external force. Generally, gray board paper should have a ply bond strength ≥120.
Moisture content: This refers to the moisture content of paper fibers, usually ranging from 7% to 9% for single gray and double gray paper of 250g-750g, and 8% to 14% for composite double gray board and gray back white board.
Thickness: Grammage table of commonly used grey board thickness:
Skewness: Skewness refers to the maximum deviation of the diagonal of a flat sheet of paper, usually expressed in millimeters. As per requirements, the skewness should not exceed 3mm.
1.2.2 Linerboard
The ability of a rigid box to present a refined and elegant appearance relies not only on the structural support provided by gray board but also on the decoration of linerboard. Linerboard, through various printing and post-press techniques, displays a rich and colorful surface. It is then laminated onto the gray board to form the main body of the rigid box. When selecting linerboard, thickness should be considered; the paper should not be too thick to avoid wrinkling during lamination, nor too thin to ensure the embossing effect is not compromised. Common types of paper used for linerboard include coated paper, matte art paper and fancy paper.
1.2.3 Medium Density Fiberboard
MDF is a type of fiberboard made from wood fibers or other plant fibers, processed with synthetic resin, and pressed under heat and pressure to create sheets. MDF is often used as the structural board for rigid boxes.
Based on its density, MDF can be categorized into high-density fiberboard, medium-density fiberboard, and low-density fiberboard. The nominal density range for medium-density fiberboard is between 650 kg/m³ and 800 kg/m³.
MDF is widely used in furniture, interior decoration, musical instruments, packaging, and other fields due to its uniform structure, fine texture, stable performance, impact resistance, and ease of processing.
Common dimensions for MDF sheets include 1220mm2440mm (48 inches96 inches) and 1830mm2440mm (72 inches96 inches). The main thickness ranges from 1mm to 30mm (0.04 inches to 1.18 inches).
1.2.4 Leather
The commonly used leather types are PU leather and synthetic leather. PU leather, made from polyurethane, is widely used in making bags, clothing, shoes, vehicle and furniture decorations. It has gained market recognition due to its versatility, large variety, and suitability for applications where traditional natural leather falls short. High-quality PU leather can even be more expensive than genuine leather, offering good shaping effects and a shiny surface.
Synthetic leather is produced by processing various PVC and PU foams or films on textile or non-woven fabric bases. It mimics natural leather and is mainly used for various synthetic leather products. Since paper is difficult to achieve a leather-like effect through post-processing, leather serves as the surface material, effectively compensating for this limitation. Leather also seamlessly integrates with various post-printing techniques such as hot stamping, embossing, UV printing, silk-screen printing, laser engraving, die-cutting, etc., making it a premium packaging solution for rigid boxes.
1.2.5 Fabric
Fabric can serve dual roles as both the surface material and the lining material in rigid boxes.
Cotton and linen textured fabrics: These fabrics offer a range of textures suitable for various aesthetic preferences and packaging needs.
Satin Fabric: Typically crafted from silk, satin fabric features a basic plain weave structure. It encompasses different weave patterns such as twill weaves, satin weaves, and specialty weaves like crepe weaves, velvet weaves, and yarn-dyed weaves.
Velvet fabric: Achieving a luxurious velvety texture, cotton fabrics undergo a velvet-raising process. The needle-punched velvet technique creates abundant velvet hairs on the surface, delivering a strong three-dimensional effect, a glossy appearance, and a plush, soft feel.
1.2.6 Auxiliary materials
Inner support materials
Ring sponge: A sponge wrapped in velvet fabric, folded to create grooves where rings and other items can be placed inside the box.
Vacuum forming: A plastic extrusion process where flat plastic sheets are heated until soft, then vacuum-sealed onto a mold surface and cooled to form shapes suitable for inner supports.
EVA (Ethylene Vinyl Acetate): Commonly known as EVA, it’s a material much harder than sponge, with characteristics like good flexibility, shock resistance, anti-slip properties, and strong compressive strength. It is used in gift boxes to secure and protect products.
Sponge: A porous material with good water absorption properties, often made from cellulose fibers or foamed plastic polymers. It’s commonly used as padding inside gift boxes.
Pearl cotton (EPE): Made from low-density polyethylene, it consists of numerous independent air bubbles formed through physical foaming. It overcomes the fragility and deformation issues of regular foam, offering advantages such as water resistance, shock absorption, sound insulation, thermal insulation, excellent malleability, strong toughness, recyclability, environmental friendliness, and high impact resistance, making it an ideal material for traditional packaging.
Structural and decorative auxiliary materials
Elastic cord: A braided material with a fabric exterior and a rubber core, available in various shapes like round or flat. For example, elastic cords are used to secure lids in place, often decorated with bow-like embellishments.
Magnets and patches: These components are used together to fix parts using magnetic attraction, especially in foldable boxes transitioning from flat to 3D configurations.
Molded plastic inserts: Plastic materials molded into required shapes according to manufacturing processes, addressing the processing needs for irregular box shapes that cannot be achieved with gray board or MDF.
PET and PVC: Polyethylene terephthalate and polyvinyl chloride are widely used for windowing and laminating in packaging products.
Jelly glue: Also known as gelatin glue, it’s primarily composed of animal protein and does not contain solvents like benzene or formaldehyde, making it non-toxic and eco-friendly. It enhances paper stiffness without deformation, mold, or bubble formation, and can also be used for logo printing as gift wrapping paper or as padding for products or rigid boxes.
Protective auxiliary materials
Wrapped or padded around the outside of rigid boxes to provide waterproofing, scratch resistance, and dust protection.
Bubble bags: Made from low-density polyethylene, these transparent soft packaging materials use air-filled bubbles to prevent product impact and provide protection against vibrations, with additional insulation properties due to the air-filled intermediate layer.
PE bags: Polyethylene (PE) bags are used for making thin films, flat PE bags, and self-sealing bags.
Copy paper: Known for its thinness, high physical strength, excellent uniformity, transparency, and surface properties like smoothness and absence of bubbles, it can be used as padding or filling paper without printing, or printed with logos for gift packaging or wrapping products or rigid boxes.
1.3 What are the uses of rigid boxes?
Rigid boxes are versatile, mainly used for packaging to protect and showcase products, enhancing their image. They’re popular for:
Gift packaging: Ideal for corporate gifts, holiday presents, weddings, and more, adding elegance and appeal to gifts.
Product packaging: Commonly used for jewelry, cosmetics, confectioneries, and high-end products, offering protection and aesthetic appeal.
Brand promotion: Showcasing brand identity with unique designs and printing techniques, enhancing brand visibility and consumer loyalty.
In summary, rigid boxes are essential for packaging, branding, and product presentation, offering both functionality and aesthetic value.
1.4 What are the benefits of rigid boxes?
Rigid boxes are versatile and primarily used for packaging to protect and showcase products, enhancing their image. They’re popular in:
Gift packaging: Ideal for corporate gifts, holiday presents, weddings, and more, adding elegance and appeal to gifts.
Product packaging: Commonly used for jewelry, cosmetics, confectioneries, and high-end products, offering both protection and aesthetic appeal.
Brand promotion: Showcasing brand identity with unique designs and printing techniques, enhancing brand visibility and consumer loyalty.
In summary, rigid boxes play a crucial role in packaging, branding, and product presentation, combining functionality with aesthetic value.
1.5 Packaging and storage
Due to their high cost and exquisite appearance, rigid boxes require careful packaging and storage for protection.
Packaging
Common packaging methods for rigid boxes include wrapping with copy paper, placing them in plastic bags or shrink-wrapping, and then placing them inside BC flute five-layer corrugated boxes. Our commonly used pallet size is 12001000mm (47.339.4 inches), with corrugated boxes stacked on the pallet. The standard stack height is 1800mm (70.9 inches) and can be adjusted up to 2500mm (98.4 inches) as needed. We also use corner protectors and top lids to prevent damage from collisions, tightening, and heavy pressure during pallet stacking.
Storage
For proper storage of rigid boxes, it’s crucial to follow these guidelines:
Suitable environment: Store cardboard boxes in a dry, ventilated warehouse, avoiding direct sunlight and moisture.
Stacking method: Boxes should be stored flat to prevent vertical stacking and ensure a moderate stack height to prevent collapse.
Avoiding harmful substances: Prevent contact with oils, acids, and alkalis to maintain cleanliness and quality.
Regular inspection: Periodically check stored boxes for damage, moisture, insect infestation, etc., and address issues promptly.
Chapter 2: Eco-friendliness of rigid boxes
2.1 Recyclability
The environmental sustainability of rigid boxes is evident in their long-term reusability. Made from high-quality and durable materials, rigid boxes can be used repeatedly for packaging, transportation, storage, decoration, and more, significantly reducing paper waste.
Furthermore, the paper we utilize is produced from both virgin pulp and recycled pulp, enabling it to be recycled for multiple cycles and ensuring environmental friendliness. Paper products are biodegradable, offering the option to recycle them into new paper or use them as plant fertilizer, thereby reducing air pollution and contributing to environmental purification.
Paper recycling involves collecting waste paper, undergoing various processing stages, and transforming it into new paper products. This process offers advantages like resource conservation, reduced deforestation, recyclability, pollution reduction, and cost-effectiveness. However, challenges such as inconsistent quality, short fiber length, and potential impurities exist in paper recycling.
In packaging applications, paper emerges as an ideal environmentally friendly material. Its recyclability, cost-effectiveness, and eco-friendliness align well with the increasing global demand for sustainable packaging solutions, making paper packaging materials the preferred choice.
2.2 Certifications from authorities
Our raw material suppliers have obtained certifications from renowned international authorities, as follows:
ISO, as the world’s largest non-governmental international standardization organization, provides various certification standards for the paper industry. These standards cover aspects such as product quality, production processes, environmental friendliness, and more. ISO certification not only ensures product quality but also serves as a passport for companies to enter the international market.
FSC is one of the most important organizations in global forest product trade. It is responsible for developing principles and standards for forest management and for auditing and approving companies applying for certification. FSC certification is particularly crucial for the paper industry as it ensures that paper products come from sustainably managed forests, contributing to the sustainable utilization and protection of global forest resources.
Additionally, other global certification bodies like SGS, BV, TUV, etc., also provide certification services related to paper products. These organizations typically have broad international recognition and extensive certification experience, enabling them to offer professional certification services to companies.
We continually strive to actively understand and learn about relevant certification standards and requirements, aiming to continuously improve product quality and management standards.
Chapter 3: Laboratory data for rigid boxes
3.1 Physical performance
Generally, the optical performance indicators of double grey board are crucial for printing and drawing papers. Transparency is measured by the degree of light passing through the paper, also represented by the maximum number of layers of ink lines visible on the sample. Opacity, on the other hand, is the reflection capacity of a single sample on a fully absorbent black backing, expressed as a percentage of the reflection capacity of several completely opaque samples. Whiteness is the reflectivity of white or near-white paper surfaces to blue light, expressed as a percentage relative to the reflectivity of a standard magnesium oxide board.
Additionally, the physical performance indicators of grey board are determined by its basis weight, thickness, tightness, porosity and air permeability, elongation, and strength. For instance, offset printing paper requires high elongation, and various strength indicators are particularly important for packaging paper, including elongation rate, burst resistance, stiffness, folding endurance, and tear resistance.
3.2 Chemical performance
Common chemical compositions of papermaking raw materials:
Chapter 4: Prices of rigid boxes
The materials and craftsmanship of rigid boxes are exquisite, leading to their relatively high prices. Therefore, when designing packaging solutions, one must consider whether to use rigid boxes, given the wide range of packaging options available at varying price points.
The pricing of rigid boxes is mainly composed of the following elements:
Greyboard: Commonly used greyboard is much thicker than regular paper, making it the largest component by weight in rigid boxes and corresponding to the highest material cost. Therefore, selecting an appropriate thickness based on the usage helps rationalize costs.
Linerboard: While linerboard is thinner, certain specialty papers may cost several times more than standard papers. Hence, it is advisable to opt for regular papers whenever possible, meeting the required specifications.
Processes: The cost difference between printing and post-printing using fully automated equipment is minimal. However, if the processes involved in rigid box assembly is complex, with a higher proportion of manual work, cost control becomes more challenging.
Transportation: Apart from foldable boxes that can be stacked for packaging, most rigid boxes are three-dimensional, requiring efficient design to maximize space utilization. For international trade, matching smaller boxes inside larger ones reduces shipping costs, facilitating smoother transactions.
Quantity: Whenever feasible within procurement needs, it’s beneficial to increase order quantities for customized products, ideally reaching the minimum quantities for equipment startup and greyboard/specialty paper customization. This helps reduce setup fees and additional costs associated with standard paper.
These considerations are essential for optimizing the cost-effectiveness of rigid box packaging solutions.
Chapter 5: Customization of rigid boxes
5.1 Types of rigid boxes
Book style
This mimics the look of a book, often featuring a flap-like cover. These boxes can have different closures like magnets, ribbons, zippers, clasps, depending on design and customer needs.
Telescope style
This encompasses various design options, including Partial Telescope Style, Full Telescope Style, and customizable variants such as Polygon Telescope Style Boxes.
Neck boxes
It can come in various designs such as Neck Boxes with Different Closure Levels, Neck Boxes with Window Patch, Neck Boxes with Hinged Cover, Solid Tube Boxes, and more, depending on the design and customer requirements.
Tray with sleeve
This type of rigid box features a tray or base that securely holds the product, which is then enclosed by a sliding sleeve. The sleeve provides an elegant and practical means of access to the product.
5.2 Design files
To ensure color accuracy and consistent document rendering, it’s best to use widely accepted software and versions internationally. This helps avoid content loss or color distortion caused by file or image conversions. Below are commonly used software and file formats:
PSD format: PSD is Photoshop’s native format, offering faster image opening and saving compared to other formats. It retains layers, channels, paths, masks, and compression schemes without data loss. However, support for this format is limited in some applications.
BMP format: BMP is Microsoft Paint’s native format and is supported by most software. It uses RLE lossless compression, ensuring minimal impact on image quality.
PDF format: PDF (Portable Document Format) is created by Adobe Systems and allows viewing electronic documents on screens. PDF files can also be embedded into HTML documents for web use.
TIFF format: TIFF (Tag Image File Format) was developed by Aldus for standardizing scanned images, widely used across Mac and PC platforms. It uses LZW lossless compression to reduce image size and can save channels, beneficial for image processing.
CDR and AI formats: These are vector file formats. Note that files between different versions of CorelDRAW may not be compatible, while Illustrator does not have this limitation.
EPS format: EPS is a format between vector and raster images, commonly used in the printing industry.
WMF format: WMF is a hybrid of bitmap and vector graphics, widely used in graphic design.
Chapter 6: How are rigid boxes made
6.1 Crafting process
Paper selection
Consider the type of paper, such as coated paper, art paper, pearl paper, etc. Consider paper thickness; it should not be too thick to avoid wrinkling during mounting, nor too thin to ensure embossing effects are visible.
Linerboard techniques
Printing involves monochrome and multicolor options, with special color printing highlighting specific hues. Post-printing techniques include glossing (high gloss, matte), lamination (glossy, matte, tactile, scratch-resistant), embossing (gold, red gold, rainbow gold, silver, laser), spot UV, flocking, and die-cutting. Hot stamping/foil stamping methods include cold stamping and hot stamping.
Hot stamping utilizes heat transfer principles to apply aluminum layers from electrochemical aluminum onto the substrate’s surface, creating a unique metallic effect. Cold stamping, as opposed to traditional hot stamping, uses specialized glue (ink) to adhere cold-stamped electrochemical aluminum, excluding the base layer, onto the substrate’s surface to achieve the stamping effect.
Greyboard selection
Greyboard, made from recycled waste paper, is categorized as single grey, double grey, full grey, or high gloss, based on client requirements for surface smoothness. Greyboard is an eco-friendly packaging material, with no set upper limit in certain situations, usually selected based on box specifications.
Die Cutting
Die-cutting is a crucial step, especially for luxury gift boxes, where precision and accuracy determine product quality. The terms for die-cutting processes are:
-Half cutting (half knife): Cutting a line or any shape on cardstock or greyboard using a die-cut blade, with a depth not less than two-thirds of the material’s thickness.
-Die-cutting score: Creating a positioning mark during die-cutting on greyboard, usually adding a half-cut or score line for easy alignment during mounting.
Slotting
Slotting is a key step in gift box production, involving a V-shaped cut on greyboard to ensure precise folding, sharp corners, and accurate alignment of box edges. The terms for slotting processes are:
Slotting: Using a slotting machine on 1-4mm thick greyboard to create V-shaped grooves, typically retaining around 0.25mm of the connecting layer.
Slotting angle: V-shaped grooves have angles like 90 degrees, 120 degrees, or other angles based on product structure.
Note: Slotting should achieve precise folding, sharp corners, and accurate alignment of box edges after bending.
Mounting
Mounting is a necessary step in gift box crafting. Depending on product requirements, materials like coated paper, art paper, velvet, leather, etc., are glued together using a gluing machine or adhesive spray, bonding firmly with greyboard. This process enhances the box’s appearance and adds value to the packaging.
6.2 Things to note
It’s customary for packaging boxes to undergo lamination before die-cutting, but laminated gift boxes follow a distinct process of die-cutting before lamination. This approach serves three key purposes: firstly, it prevents potential damage to external packaging materials, preserving their aesthetic appeal. Secondly, it enhances the overall visual harmony of gift boxes by fully concealing the support structure after lamination, creating an artistic and captivating appearance. Lastly, for box types with complex structures, manual lamination remains essential as machines cannot replicate this process.
6.3 Turnaround
The construction of rigid boxes is precise and involves complex craftsmanship, often requiring manual assembly. As a result, their production speed is significantly slower compared to products that can be manufactured on assembly lines. On average, for simpler structures with semi-automatic machinery assistance and a team of 4-6 people, the daily output is around 3000 units, which is considered typical. However, for more intricate structures such as irregular-shaped boxes without mechanical assistance, the daily output ranges from 600 to 1000 units, with a workforce of at least 6 people depending on the production process. We will prioritize meeting the delivery deadlines specified by our customers based on their order requirements.
Chapter 7: Quality inspection
7.1 Why quality inspection is important
Rigid boxes are known for their high cost, necessitating stringent quality inspections to maintain a high yield of finished products and avoid significant losses for both manufacturers and customers. These boxes also serve as a platform for showcasing a company’s culture and promoting its products. Therefore, the presence of defective items can have a negative impact on the brand image in the eyes of customers. Implementing strict quality checks at each production stage not only improves efficiency but also prevents the need for rework, saving time and material costs. This comprehensive quality inspection ensures the safety of premium boxes in terms of their physical and chemical properties, providing peace of mind to users and customers alike.
7.2 How many samples will be checked
7.3 Quality inspection criteria
7.4 Common problems and solutions in rigid box production
During the manufacturing process of rigid boxes, each step carries hidden quality risks. These risks are not due to incomplete process design or inadequate equipment performance but are mostly caused by a lack of quality awareness and uneven skill levels among operators, coupled with inadequate process control. These factors often lead to quality defects, posing the biggest challenge to stable quality in rigid box production. Improving the quality awareness of managers and operators is crucial and the most effective way to avoid defects.
Common defects or quality control points
Loose edges: Insufficient adhesion and floating between paper and greyboard at the four corners of the box after paper lamination.
Creases: Irregular and uneven folding of the paper surface after lamination, resulting in irregular folds.
Corner damage: Paper damage and whitening at the four corners of the box after paper lamination.
Greyboard exposure (Baseboard Exposure): Misalignment of laminated paper causing greyboard to be exposed due to inaccurate die-cutting or offset positioning during lamination.
Bubbling: Irregular and varying-sized bulges on the surface of the box.
Glue stains: Residual traces of glue on the surface.
Protrusions (Blisters): Granular residues underneath the packaging material causing localized bulges, disrupting the smoothness of the box surface.
Uneven edges: Inconsistent height between adjacent edges after half-cutting or slotting of greyboard.
Water ripples: Longitudinal or lateral irregularities or small bubbles resembling water ripples on the edges of the box, caused by improper scraping during edge finishing.
To address these issues, it’s important to choose suitable adhesives, different surface papers, and boards for rigid box production. Considerations for adhesive selection:
For corrugated paper, starch-based adhesives are suitable due to their low cost. Higher-quality white cardboard may require white latex adhesive, while premium boxes might need water-based yellow adhesive. Operational requirements should be considered, such as the need for quick-drying adhesives in manual production and slower-drying adhesives for large-area bonding in machine operations. It’s important to avoid mixing different types of adhesives and ensure each adhesive has its own application tools or machines. Clean machines and adhesive tools thoroughly when switching adhesives, and dilute adhesives with water cautiously to maintain drying time and adhesive properties. The water dilution ratio typically ranges from 10% to 30%, depending on the adhesive type. These measures significantly enhance the quality and stability of rigid box production.
Chapter 8: Development trends
The future of rigid boxes will focus on five key areas:
-Embracing personalization and customization to meet diverse customer demands.
-Increasing the use of green and sustainable materials to align with environmental priorities.
-Integrating digital and smart technologies for enhanced efficiency and functionality.
-Fostering cross-industry collaboration and innovation for novel solutions.
-Elevating brand identity and cultural relevance to resonate with consumers on a deeper level.
Chapter 9: Conclusion
Rigid boxes play a crucial role in enhancing product value, strengthening brand image, ensuring product safety, and driving sales growth. With increasing consumer awareness of environmental protection and sustainability, the design and production of rigid boxes are increasingly focusing on environmental friendliness and sustainability. By using recyclable, biodegradable materials and eco-friendly printing processes, rigid boxes can meet aesthetic and practical requirements while reducing environmental impact, achieving a win-win situation for economic and social benefits.
