PVC foaming layer composition and PVC artificial leather

Abstract

The present invention relates to a PVC foam layer composition comprising a PVC resin, a plasticizer and a physical blowing agent, in which the plasticizer is a trimellitic plasticizer having a viscosity, measured at 20 DEG C according to ASTM D445, of from 60 mPa * S to 100 mPa * S, or the plasticizer is an orthophthalic plasticizer having a viscosity, measured at 20 DEG C according to ASTM D445, of from 65 mPa * S to 94 mPa * S. The invention further relates to PVC artificial leather which comprises a foaming layer formed by the PVC foaming layer composition. The technical problem to be solved by the invention is to reduce foaming slurry dripping.

Description

Technical Field

[0001] The invention relates to a PVC foaming layer composition and a PVC artificial leather. Background Art

[0002] Artificial leather is widely used in automotive interior materials, such as polyvinyl chloride (PVC) artificial leather. PVC artificial leather comprises a PVC leather layer, such as a dense epidermis layer and / or a porous foaming layer. The foaming layer is obtained by adding a foaming agent for foaming. The foaming agent includes a chemical foaming agent and a physical foaming agent.

[0003] With the improvement of environmental protection and odor requirements of OEMs, chemical foaming is gradually being replaced by physical foaming in PVC artificial leather, so corresponding physical foaming products, also known as low-odor PVC artificial leather, have been developed. However, with the mass production of physical foaming PVC artificial leather, foaming and dripping began to occur frequently on the coating production line, resulting in a rapid increase in product scrap rate and a great risk of customer complaints. Foaming dripping refers to a phenomenon in which the slurry drips unevenly onto the surface during the scraping process of the foaming slurry, causing convex points to form on the surface of the foaming layer after foaming. When observed in the cross section of the product, the thickness of the foaming layer at the convex point position is significantly greater than the thickness of the foaming layer in other areas. This dripping problem does not exist in traditional chemical foaming.

[0004] The dripping of slurry is affected by the viscosity and fluidity of the slurry. The viscosity and fluidity of the foaming slurry are affected by the various components in the slurry. Only controlling the viscosity of the slurry often cannot ensure the desired product performance. At present, in order to improve the dripping problem of physical foaming slurry, plasticizers of different categories and different viscosities are usually compounded. However, the compounding of different categories of plasticizers makes the processing technology complicated, the cost increases, affects the product performance, and makes the cleaning in the process operation difficult. The prior art also proposes equipment to remove the hanging slurry online, which will also complicate the process.

[0005] Therefore, the present invention needs to propose a new technical solution to solve at least one of the above-mentioned technical problems. Summary of the invention

[0006] Based on the above prior art, the object of the present invention is to reduce foaming and dripping.

[0007] To achieve the above technical objectives, the present invention provides a PVC foam layer composition, comprising a PVC resin, a plasticizer and a physical foaming agent, wherein the plasticizer is a benzene plasticizer, and its viscosity measured at 20°C according to ASTM D445 is between 60mPa*S and 100mPa*S, or the plasticizer is an orthophthalic plasticizer, and its viscosity measured at 20°C according to ASTM D445 is between 65mPa*S and 94mPa*S.

[0008] The inventors have found that the use of plasticizers of the same category is more conducive to maintaining the desired product performance while obtaining the appropriate viscosity than the compounding of plasticizers of different categories. The effects of different categories of plasticizers on product performance, such as heat resistance, cold resistance, and processability, vary greatly. Depending on the different product performances, the application sites are different. For example, products with low precipitation and good heat resistance are suitable for areas with a lot of light, such as dashboards, while products with cold resistance but slightly poor precipitation and heat resistance are suitable for areas with less light. When different categories of plasticizers are compounded, the viscosity limit of the plasticizer needs to take into account the compounding ratio, otherwise the product performance will fail while adjusting to obtain the appropriate viscosity.

[0009] The inventors further discovered through a large number of experiments that when only a benzene plasticizer is used and its viscosity is adjusted to 60mPa*S to 100mPa*S (ASTM D445, 20°C), or when only an orthophthalic plasticizer is used and its viscosity is adjusted to 65mPa*S to 94mPa*S (ASTM D445, 20°C), the dripping of the foaming slurry can be effectively reduced or even prevented.

[0010] Advantageously, the plasticizer is a single plasticizer. When a single plasticizer is used and has the aforementioned defined viscosity, dripping can be improved.

[0011] Advantageously, the plasticizer is compounded by plasticizers of the same category and different viscosities. When the above-defined viscosity is obtained by compounding plasticizers of the same category and different viscosities, the dripping can be improved. Here, the plasticizer of the same category refers to, for example, only using a benzene plasticizer or only using an orthophthalic plasticizer. Different chain structures are involved in plasticizers of the same category, resulting in different viscosities. For example, benzene plasticizers include plasticizers of different viscosities such as tris(2-ethylhexyl) trimellitate, tri(n-octyl-n-decyl) trimellitate, and tri-isooctyl trimellitate; orthophthalic plasticizers include plasticizers of different viscosities such as dioctyl phthalate, diisooctyl phthalate, diisodecyl phthalate, and dibutyl phthalate.

[0012] Advantageously, the physical blowing agent is a low boiling point microsphere physical blowing agent.

[0013] Advantageously, the PVC foam layer composition does not contain chemical blowing agents.

[0014] Advantageously, the PVC foam layer composition comprises 55 to 65 parts by weight of PVC resin and 35 to 45 parts by weight of plasticizer.

[0015] Advantageously, the PVC foam layer composition comprises 0.1 to 2 parts by weight of a physical foaming agent based on 100 parts by weight of the total weight of the PVC resin and the plasticizer.

[0016] Also advantageously, the PVC foam layer composition comprises 0.5 to 4 parts by weight of a stabilizer based on 100 parts by weight of the total weight of the PVC resin and the plasticizer.

[0017] The PVC foam layer composition according to the present invention can be used to prepare the foam layer of PVC artificial leather.

[0018] Accordingly, the present invention also provides a PVC artificial leather, comprising a foaming layer formed by the PVC foaming layer composition according to the present invention. The above-mentioned features and effects of the PVC foaming layer composition are also applicable to PVC artificial leather, which will not be repeated here.

[0019] Advantageously, the PVC artificial leather comprises a PVC skin layer bonded to the foaming layer.

[0020] Advantageously, the PVC artificial leather comprises a base fabric layer bonded to the foaming layer, for example, via an adhesive layer. The base fabric layer, as the main supporting structure of the PVC artificial leather, ensures the mechanical strength of the entire artificial leather and plays a very important role in the entire structure. The adhesive can penetrate into the base fabric layer, thereby tightly bonding the PVC leather layer to the base fabric layer.

[0021] Advantageously, the outer surface of the PVC artificial leather has a paint layer, thereby improving the surface properties of the artificial leather such as stain resistance and wear resistance.

[0022] The PVC artificial leather according to the present invention can be used in, for example, the field of automobile interior decoration.

[0023] The advantages of the present invention are: reducing foaming and dripping, thereby reducing the scrapping of product convex points; improving production efficiency, without the need to slow down or stop the line for cleaning; and having no difference in plasticizer types, resulting in stable product performance. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention is clearly and completely described below in combination with embodiments and comparative examples. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0025] Preparation of PVC foam layer:

[0026] 55 parts by weight of PVC powder, 45 parts by weight of plasticizer, 1 part by weight of low-boiling point microsphere physical foaming agent, 1.5 parts by weight of stabilizer, and 0.1 parts by weight of carbon black were mixed to prepare a PVC foaming layer slurry.

[0027] The K value of the PVC powder is 75 (measured according to ISO 1628-2), and the mass fraction of the residue passing through a 0.125 mm sieve is ≤ 0.15 g / kg (measured according to the residue test of ISO 787-18). The formula and viscosity of the plasticizer are listed in Table 1, Table 2, and Table 3, respectively.

[0028] Send release paper, and coat the PVC foaming layer slurry on the release paper. Observe whether slurry dripping occurs during the slurry coating process. Evaluate the observation results: if there is no slurry dripping in 3 consecutive batches within 2000 meters during production, the formula is evaluated as OK; if slurry dripping occurs within 3 batches, it is evaluated as NOK. The results are shown in Table 1, Table 2, and Table 3.

[0029] After coating, it is dried and the release paper is peeled off to obtain the PVC foam layer.

[0030] Table 1: Examples 1 to 4 and Comparative Examples 1 to 3

[0031]

[0032] Table 2: Examples 5 to 7 and Comparative Examples 4 to 5

[0033]

[0034] Table 3: Comparative Example 6

[0035]

[0036] Note: In Table 1, Table 2 and Table 3, the content of each component of the plasticizer is expressed as a percentage based on the total weight of the plasticizer, and the viscosity is measured at 20°C according to standard ASTM D445.

[0037] As shown in Table 1, different viscosities of the benzene plasticizers 1, 2, and 3 are used alone or in combination, thereby adjusting the different viscosities of the plasticizers. From the evaluation results, it can be seen that when the benzene plasticizer is used alone or in combination and the viscosity of the plasticizer is controlled at 60 to 100 mPa*S, the foaming and dripping can be effectively reduced, thereby reducing the scrapping of the convex points of the product.

[0038] As shown in Table 2, orthophthalic plasticizers 1 and 2 of different viscosities are used alone or in combination, thereby adjusting different viscosities of the plasticizers. From the evaluation results, it can be obtained that when orthophthalic plasticizers are used alone or in combination and the viscosity of the plasticizer is controlled at 65 to 94 mPa*S, foaming and dripping can be effectively reduced, thereby reducing the scrapping of convex points of the product.

[0039] In addition, the PVC foamed layers obtained from Examples 1 to 7 and Comparative Examples 1 to 6 were subjected to the following performance tests:

[0040] Heat resistance is tested at 120°C for 336 hours. At the end of the test, the sample is evaluated according to the gray standard sample DIN EN20105-A02, which is required to be greater than or equal to GM4, and no color mutation is allowed; the hand feel is evaluated based on the original sample that has not been tested for heat resistance, and it must not become hard, brittle or sticky. If the above conditions are met, the result is evaluated as OK; otherwise, the result is evaluated as NOK.

[0041] The bending resistance is tested according to the standard ISO 5402-1:2017(E) at -20°C and 30,000 times. At the end of the test, if there are no cracks or fissures on the surface of the sample, the result is evaluated as OK; otherwise, if there are cracks or fissures on the surface of the sample, the result is evaluated as NOK.

[0042] Experimental results: The foamed layers obtained in Examples 1 to 4 and Comparative Examples 1 to 3 using only the benzene plasticizers were all OK in the heat resistance test at 120°C and 336h, so the product performance was not affected and they were suitable for parts with a lot of light, such as dashboards. The foamed layers obtained in Examples 5 to 7 and Comparative Examples 4 to 5 using only the orthophthalic plasticizers were all OK in the bending resistance test at -20°C and 30,000 times, so the product performance was not affected and they were suitable for areas in the car with little light. However, the foamed layer obtained in Comparative Example 6 using a combination of benzene plasticizers and orthophthalic plasticizers was NOK in the heat resistance test at 120°C and 336h and the bending resistance test at -20°C and 30,000 times. Therefore, although there was no foaming dripping, the product performance was affected and it could not be applied to any part of the car.

[0043] In another embodiment, PVC artificial leather is further prepared. For this, PVC skin layer slurry is coated on release paper and dried; then PVC foaming layer slurry is coated and dried; then PVC adhesive layer slurry is coated; then base fabric is attached and dried; release paper is peeled off; paint is printed on the surface of PVC skin layer and embossed, thereby obtaining PVC artificial leather product. The preparation of foaming layer slurry refers to the above-mentioned Examples 1 to 7. The effect of different plasticizer formulas on product performance is consistent with the experimental results of the above-mentioned foaming layer.

[0044] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those skilled in the art, the above-mentioned various technical features can be arbitrarily combined to make various modifications and improvements without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered as the protection scope of the present invention.

Claims

1. A PVC foam layer composition, comprising a PVC resin, a plasticizer and a physical foaming agent, characterized in that: The plasticizer is a benzene plasticizer, and its viscosity measured at 20°C according to ASTM D445 is 60mPa*S to 100mPa*S, or the plasticizer is an orthophthalic plasticizer, and its viscosity measured at 20°C according to ASTM D445 is 65mPa*S to 94mPa*S.

2. The PVC foam layer composition according to claim 1, characterized in that: The plasticizer is a single plasticizer.

3. The PVC foam layer composition according to claim 1, characterized in that: The plasticizer is compounded from plasticizers of the same category but with different viscosities.

4. The PVC foam layer composition according to claim 1, characterized in that: The physical foaming agent is a low-boiling point microsphere physical foaming agent.

5. The PVC foam layer composition according to any one of claims 1 to 4, characterized in that: The PVC foam layer composition does not contain a chemical foaming agent.

6. The PVC foam layer composition according to any one of claims 1 to 4, characterized in that: The PVC foam layer composition comprises 55 to 65 parts by weight of PVC resin and 35 to 45 parts by weight of plasticizer.

7. The PVC foam layer composition according to claim 6, characterized in that: The PVC foam layer composition comprises 0.1 to 2 parts by weight of a physical foaming agent based on 100 parts by weight of the total weight of the PVC resin and the plasticizer.

8. The PVC foam layer composition according to claim 6, characterized in that: Based on 100 parts by weight of the total weight of the PVC resin and the plasticizer, the PVC foam layer composition comprises 0.5 parts by weight to 4 parts by weight of the stabilizer.

9. The PVC foam layer composition according to any one of claims 1 to 4, characterized in that: The PVC foaming layer composition is used for preparing the foaming layer of PVC artificial leather.

10. A PVC artificial leather comprising a foamed layer formed from the PVC foamed layer composition according to any one of claims 1 to 9.

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