Archive for month: October, 2023

The principle of vacuum plasticization of PVC decorative films involves the use of heat and pressure to soften and shape the PVC material.
The process begins by heating the PVC decorative film, which is typically in sheet or roll form, to a specific temperature range. This temperature is typically above the glass transition temperature of PVC, which is around 70-90°C.
Once heated, the PVC film is placed over a mold or substrate with the desired shape or texture. The mold is usually made of metal or another heat-conductive material and may have a textured surface to create a specific design or pattern on the PVC film.
During the heating and softening process, the PVC film is placed close to the medium density fiberboard after spraying adhesive. The air between the PVC film and the medium density fiberboard adhesive film is extracted using vacuum, and the PVC film is tightly adhered to the medium density fiberboard using atmospheric pressure. This process is called vacuum plasticizing.
Characteristics of PVC blister film:
The adhesive used for vacuum plastic film application is vacuum plastic, which is mainly water-based polyurethane adhesive and mixed with other resins. In principle, hot melt adhesive or solvent based adhesive can also be used, but water-based adhesive is non-toxic, odorless, affordable, and suitable for mechanized operation.
The biggest feature of this process is that it does not require further painting or coating, and it is a paintless process. In addition, it can also cover concave and convex grooves, curved edges, and hollow carving pieces, which are incomparable to other processes.
A vacuum is then applied to the backside of the PVC film, which helps to create a pressure difference between the two sides of the film. This pressure difference forces the softened PVC material to conform to the shape of the mold or substrate.
As the vacuum is applied, the air trapped between the PVC film and the mold is removed, creating a tight seal between the film and the mold surface. This allows the PVC material to closely adhere to the mold and take on its shape.
Once the PVC film has completely conformed to the mold, the vacuum is released, and the film is cooled rapidly to solidify the material and maintain its shape. This cooling process can be done using water or air, depending on the specific requirements of the application.
The end result is a decorative film that has been transformed into a specific shape or texture, ready to be used for various applications such as furniture, interior design, or automotive trim.PVC decorative film has a discounted price and is easy to use, making it highly popular in markets around the world. If you encounter any problems or confusion when selecting PVC decorative films, please feel free to contact us at ECO PVC FILM, and we will provide you with the best service and quality. The super high cost-effectiveness will make you 100% satisfied.

 

The vacuum plastic coating process, also known as vacuum metallizing or vacuum deposition, can encounter various challenges and problems during its execution. These issues can impact the quality of the coated products and the efficiency of the manufacturing process. Here are some common problems encountered in the vacuum plastic coating process and their potential solutions:
Pinholes or Porosity in Coating:
Problem: Small holes or pores in the coating can lead to reduced barrier properties and aesthetics.
Solution: Improve the cleanliness of the substrate surface, adjust the coating parameters, and ensure proper degassing of the vacuum chamber to minimize contamination and porosity.
Uneven Coating Thickness:
Problem: Variations in coating thickness across the substrate can result in inconsistent appearance and performance.
Solution: Maintain proper control over deposition rates, substrate rotation or movement, and coating source positioning to ensure uniform deposition.
Adhesion Issues:
Problem: Poor adhesion of the coating to the substrate can result in delamination or flaking.
Solution: Pre-treat the substrate surface with techniques like plasma cleaning or corona treatment to improve adhesion. Ensure proper substrate cleaning and preparation.
Contamination and Impurities:
Problem: Contaminants in the vacuum chamber or on the substrate can lead to defects in the coating.
Solution: Maintain a clean environment within the vacuum chamber, regularly clean the chamber and fixtures, and use high-purity source materials.
Stress and Cracking:
Problem: High residual stress in the coating can lead to cracking or peeling.
Solution: Optimize deposition parameters, such as temperature and deposition rate, to reduce stress. Use stress-relief layers if necessary.
Substrate Warping or Deformation:
Problem: Some plastics may deform or warp under the high vacuum and temperature conditions.
Solution: Choose substrates that are suitable for vacuum coating or implement temperature control methods to minimize substrate distortion.
Phenomenon 1: Bubbling in the groove
Reason analysis:
1. The temperature or pressure does not meet the requirements, resulting in false suction;
2. Insufficient adhesive amount, insufficient spraying amount, or adhesive leakage from the board;
3. Insufficient preheating (softening PVC film) or blistering time (forming time);
4. After vacuum molding, remove the pressure before the temperature drops.
5. The heat resistance of the adhesive itself is not sufficient.
Solution:
1. Increase temperature or vacuum;
2. Increase the amount of glue applied and select high-quality boards;
3. Increase preheating or molding time;
4. After vacuum molding, the temperature should be cooled to room temperature or slightly higher before withdrawing the vacuum.
5. Use with curing agent.
Phenomenon 2: Local blistering
Reason analysis:
1. Uneven glue spraying results in a small amount of local glue, leading to a decrease in bonding strength;
2. The problem with PVC film is that it contains plasticizers, which can easily migrate to the surface during aging or heating, affecting the bonding strength;
3. There is a problem with the heating pipe inside the blister machine, causing uneven temperature.
Solution:
1. Try to ensure a uniform amount of adhesive spraying;
2. Use high-quality PVC film;
3. Timely maintenance of equipment.
Phenomenon 3: Unable to hold or shrink the edge
Reason analysis:
1. When vacuuming, the side temperature is too low or the vacuum degree is insufficient;
2. Insufficient temperature resistance of adhesive;
3. After vacuum molding, remove the pressure before the temperature drops.
Solution:
1. Increase temperature or vacuum;
2. Use with curing agent;
3. After vacuum molding, the temperature should be cooled to room temperature or slightly higher before withdrawing the vacuum.

 

The medium density substrate is processed into various linear shapes and then covered with PVC films of various brightness, colors, and textures, making the products rich and colorful, creating a wide range of choices for consumers. However, the quality of products manufactured using this technology varies greatly. The reasons for these differences are not only due to the factors of the substrate and decorative material PVC itself, but also the control of process parameters during the processing process.

1、 Working principle of membrane press

By utilizing the plasticity of PVC and adjusting and controlling the membrane pressure time, equipment chamber temperature, and air pressure, PVC is heated and pressurized to coat the surface of the workpiece.

2、 The working process of the membrane press

(1) Place the workpiece on the workbench;

(2) The workbench enters directly below the heating plate;

(3) Close the heating plate with the workbench;

(4) The air between the heating plate and the silicone film is extracted, and the silicone film is adsorbed onto the heating plate for heating;

(5) After reaching the set time, compressed air is injected between the heating plate and the silicone film. The silicone film is in close contact with PVC, and the workpiece and PVC are heated. At the same time, PVC is softened, and the temperature at the edge of the plate reaches the activation temperature of the adhesive;

(6) The air between the workbench and PVC is quickly extracted to form a vacuum, and then compressed air is injected between the PVC and the heating plate. PVC is wrapped on the plate under the set pressure and temperature.

A membrane press, also known as a vacuum membrane press or membrane vacuum press, is a machine used in woodworking and the manufacturing of laminated products. It is primarily used to apply decorative or functional laminates, veneers, and films onto various substrates like wood, MDF (Medium-Density Fiberboard), particleboard, and foam. Here’s how a typical membrane press works:

Preparation:

First, the operator prepares the substrate (e.g., a wooden panel or piece) by applying adhesive to it. This adhesive will bond the decorative material or laminate to the substrate when subjected to heat and pressure.

Laying the Decorative Material:

The decorative material, which is typically a flexible PVC or thermoplastic film with a decorative pattern (such as wood grain or solid color), is placed over the adhesive-coated substrate. This material will become the visible surface of the finished product.

Positioning in the Press:

The substrate and decorative material are then placed in the membrane press. The press consists of a chamber or frame with a flexible, heat-resistant membrane or silicone bag suspended above it.

Creating a Seal:

The membrane is lowered to make contact with the decorative material and substrate. It should form a tight seal around the edges to create an airtight chamber.

Vacuum and Heat:

The press is equipped with a vacuum system. When activated, it removes the air from the chamber between the membrane and the substrate. This creates a vacuum or negative pressure inside the chamber.

Heating Elements:

The press also contains heating elements, such as electric heating panels or infrared lamps. These elements generate heat and are positioned above or below the membrane.

Activation:

The vacuum and heat are activated simultaneously. The vacuum draws the flexible membrane tightly around the decorative material and substrate, pressing them together with even pressure. At the same time, the heat activates the adhesive, causing it to bond the decorative material to the substrate.

Curing and Cooling:

The heating elements maintain the desired temperature for the adhesive to cure properly. This curing process may take a few minutes. After curing, the temperature is gradually reduced to allow the bonded materials to cool and set.

Release and Removal:

Once the curing and cooling process is complete, the vacuum is released, and the flexible membrane is lifted. The bonded decorative material is now securely attached to the substrate, conforming to its shape.

Trimming and Finishing:

The finmming and Finishing:ished product, with the decorative material firmly adhered to the substrate, may undergo additional finishing processes such as edge trimming, sanding, or further machining to achieve the desired final dimensions and appearance.

The membrane press ensures a consistent and even application of decorative materials, eliminating wrinkles, air bubbles, and other defects that can occur with manual or less controlled laminating methods. It is widely used in the production of furniture, cabinetry, doors, wall panels, and other laminated products where high-quality surface finishes are essential.