Leather for car seats and process for the preparation thereof

Abstract

This invention relates to the field of foamed materials technology, and proposes a type of leather for automotive seats and its preparation process. The automotive seat leather comprises, from bottom to top, a base layer, a foamed layer, and a top layer. The foamed layer comprises the following raw materials by weight: 100 parts PVC resin, 30-50 parts filler, 30-70 parts plasticizer, 3-6 parts foaming agent, 3.7-10.8 parts additives, and 3-5 parts colorant. The PVC resin is composed of a first PVC resin and a second PVC resin, and the first and second PVC resins have different average degrees of polymerization. This technical solution solves the problem of insufficient strength in automotive seat leather in related technologies.

Description

Technical Field

[0001] This invention relates to the field of foam materials technology, specifically to a type of leather for automotive seats and its preparation process. Background Technology

[0002] Leather used in car seats is a core material for the function and decoration of car interiors. In daily use, it must withstand the pressure of human body sitting, friction, and environmental stresses such as temperature differences and ultraviolet radiation inside the car. At the same time, it must meet environmental and safety standards such as low volatile organic compounds (VOCs) and no heavy metals. It is a key component that affects the car riding experience, interior durability, and user safety perception.

[0003] As the automotive industry places increasing demands on interior quality, the mechanical properties of leather used in car seats have become one of the core evaluation indicators. Among them, tensile strength directly determines the leather's ability to resist tearing and deformation during long-term use, but existing automotive seat leathers generally have shortcomings in tensile strength.

[0004] When a seat is repeatedly pressed down, causing localized stretching of the leather, insufficient tensile strength can lead to problems such as cracking at the seams, breakage of the surface texture, and even delamination. This not only affects the aesthetics but may also expose the underlying material due to leather damage, reducing seat support. Therefore, it is essential to develop a type of automotive seat leather with excellent mechanical properties. Summary of the Invention

[0005] This invention proposes a type of leather for automotive seats and its preparation process, which solves the problem of insufficient strength of automotive seat leather in related technologies.

[0006] The technical solution of the present invention is as follows: The present invention proposes a leather for automobile seats, which comprises, from bottom to top, a base layer, a foam layer and a surface layer. The foam layer comprises the following raw materials in parts by weight: 100 parts of PVC resin, 30-50 parts of filler, 30-70 parts of plasticizer, 3-6 parts of foaming agent, 3.7-10.8 parts of additives, and 3-5 parts of colorant. The PVC resin is composed of a first PVC resin and a second PVC resin, and the average degree of polymerization of the first PVC resin and the second PVC resin is different.

[0007] As a further technical solution, the average degree of polymerization of the first PVC resin is 1135, and the average degree of polymerization of the second PVC resin is 1470.

[0008] In the raw materials of the automotive seat leather of this invention, the first PVC resin has an average degree of polymerization of 1135. The short molecular chains serve as flexible connecting units, filling the gaps between the long chains. Through the movement of chain segments, tensile stress is buffered, avoiding brittle fracture caused by excessive entanglement of the long chains. The second PVC resin has an average degree of polymerization of 1470. The long molecular chains form a tough skeleton with high intermolecular entanglement density, providing core tensile support for the foam layer. The combination of the two makes the automotive seat leather both tear-resistant and not easily brittle under repeated sitting pressure, thus improving the strength of the automotive seat leather.

[0009] As a further technical solution, the mass ratio of the first PVC resin to the second PVC resin is 6~7:3.

[0010] As a further technical solution, the filler includes one or more of calcium carbonate, talc, and kaolin, preferably calcium carbonate; The plasticizer includes one or more of dioctyl phthalate, dibutyl phthalate, and diisononyl phthalate; preferably dioctyl phthalate. The additives comprise the following components by weight: 1-5 parts stabilizer, 0.1-0.3 parts oxidized polyethylene wax, 1-1.5 parts stearic acid, 1-3 parts antimony trioxide, 0.3-0.5 parts antioxidant, and 0.3-0.5 parts ultraviolet absorber; The foaming agent is a microsphere foaming agent; The colorant includes one or more of carbon black, phthalocyanine blue, and phthalocyanine green, preferably carbon black.

[0011] The invention adds a plasticizer to the raw material of the leather for car seats, which can insert between the PVC molecular chains to weaken the intermolecular forces, giving the material flexibility and processability, making the foam layer more fluid during calendering, facilitating tight bonding with the fabric base layer, and reducing processing defects.

[0012] The present invention adds stabilizers, antioxidants and ultraviolet absorbers to the raw materials of automotive seat leather, which can inhibit the thermal degradation and oxidative degradation of PVC resin during processing and use, inhibit the oxidative aging of PVC resin, protect the leather from photoaging, and improve the service life of automotive seat leather.

[0013] This invention adds a microsphere foaming agent to the raw material of automotive seat leather, allowing the foamed layer material to be calendered in a foamed state during the calendering process. This replaces the traditional AC foaming agent foaming process in a foaming furnace, directly eliminating the high-temperature furnace heating foaming step, greatly simplifying the process and improving production efficiency. At the same time, it reduces the equipment footprint, further compressing production site and equipment investment costs, bringing significant economic benefits to enterprises. In addition, during the traditional high-temperature furnace heating foaming process, the high-temperature environment accelerates the release of volatile components such as residual monomers and other additives in PVC resin, generating a large amount of VOC gas. However, microsphere foaming does not require a high-temperature environment and can significantly inhibit the release of volatile components in the PVC system, reducing VOC gas emissions.

[0014] As a further technical solution, the stabilizer is KGDM871, the antioxidant is antioxidant 619, and the ultraviolet absorber is uv-531.

[0015] As a further technical solution, the filler is a composite filler, and the preparation method of the composite filler includes the following steps: dispersing a hydroxyl-containing N-substituted acrylamide compound in a solution, adding the filler, mixing and drying to obtain the composite filler.

[0016] This invention adds composite fillers to the raw materials of automotive seat leather. After the fillers are compounded with N-substituted acrylamide compounds containing hydroxyl groups, the hydroxyl groups in the N-substituted acrylamide compounds can form hydrogen bonds with the hydroxyl groups on the surface of the fillers, thereby fixing them on the surface of the fillers. This introduces functional groups such as amide bonds and double bonds into the surface of the fillers, promotes the uniform dispersion of the fillers, enhances the bonding force of the fillers with the PVC resin matrix, and improves the tear strength of the automotive seat leather.

[0017] As a further technical solution, the solution is a methanol-water solution, wherein the mass ratio of methanol to water in the methanol-water solution is 1:1.

[0018] As a further technical solution, the mass ratio of the solution to the filler is 4 to 6:1, for example, it can be 4:1, 5:1, or 6:1, preferably 5:1.

[0019] As a further technical solution, the mixing time is 3 to 5 hours, for example, it can be 3 hours, 3.5 hours, 4 hours, 4.5 hours, or 5 hours, preferably 4 hours.

[0020] As a further technical solution, the mass ratio of the filler to the hydroxyl-containing N-substituted acrylamide compound is 20:1.5~2.

[0021] As a further technical solution, the hydroxyl-containing N-substituted acrylamide compound includes one or more of N-(2-hydroxypropyl)methacrylamide, N-p-hydroxyphenylacrylamide, and N-(hydroxymethyl)acrylamide.

[0022] As a further technical solution, the material of the base layer includes one of knitted fabric, non-woven fabric, and artificial leather fabric, preferably artificial leather fabric.

[0023] As a further technical solution, the surface layer comprises the following raw materials in parts by weight: 100 parts of second PVC resin, 30-50 parts of calcium carbonate, 30-70 parts of dioctyl phthalate, 1-5 parts of stabilizer, 0.1-0.5 parts of oxidized polyethylene wax, 1-1.5 parts of stearic acid, 1-3 parts of antimony trioxide, 0.3-0.5 parts of antioxidant, and 0.3-0.5 parts of ultraviolet absorber.

[0024] As a further technical solution, the stabilizer is DM871, the antioxidant is antioxidant 619, and the ultraviolet absorber is uv-531.

[0025] This invention also proposes a manufacturing process for automotive seat leather, comprising the following steps: S1. Mix the foaming layer raw materials to obtain a foaming layer premix; extrude and calender the foaming layer premix onto the fabric base layer to obtain a foaming layer; mix the surface layer raw materials to obtain a surface layer premix; extrude and calender the surface layer premix onto the foaming layer to obtain a semi-finished product. S3. The surface of the semi-finished product is treated with a treatment agent and then embossed. After inspection, the leather for car seats is obtained.

[0026] As a further technical solution, in step S1, the mixing temperature of the foaming layer raw materials is 80~90℃.

[0027] As a further technical solution, in step S1, the mixing temperature of the surface layer raw materials is 80~90℃.

[0028] As a further technical solution, in step S1, the extrusion temperatures of the foaming layer premix and the surface layer premix are each independently 120~200℃.

[0029] The working principle and beneficial effects of this invention are as follows: In the foamed layer of the automotive seat leather of this invention, a first PVC resin and a second PVC resin with different average degrees of polymerization are added as raw materials. The two are used in combination. The PVC resin with a lower average degree of polymerization has shorter molecular chains and higher fluidity. This not only reduces the brittleness of the PVC resin with a higher average degree of polymerization due to excessive intermolecular entanglement and alleviates the decrease in tensile strength, but also forms a denser and more flexible molecular network structure through the cross-entanglement of short and long chains, thereby improving the strength of the automotive seat leather. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] In the following examples and comparative examples: First PVC resin: average degree of polymerization 1135, model PG680, manufacturer is SCG Chemical Public Company Limited; The second PVC resin has an average degree of polymerization of 1470, is model PF741, and is manufactured by SCG Chemicals Public Company Limited. Calcium carbonate: Heavy calcium carbonate, with an average particle size of 5000 mesh; Foaming agent: Model 031DU40; Stabilizer: Model KGDM871, purchased from Jinan Jincaiyang New Material Technology Co., Ltd. Treatment agent: Model PU 9300, purchased from Zhejiang Demeboshida Polymer Materials Co., Ltd.

[0032] Example 1 A manufacturing process for automotive seat leather includes the following steps: S1. Mix 100 parts of PVC resin, 30 parts of calcium carbonate, 30 parts of dioctyl phthalate, 3 parts of foaming agent, 3.7 parts of additives, and 3 parts of carbon black at 80°C to obtain a foamed layer premix. The additives consist of the following components by weight: 1 part of stabilizer, 0.1 part of oxidized polyethylene wax, 1 part of stearic acid, 1 part of antimony trioxide, 0.3 parts of antioxidant 619, and 0.3 parts of UV-531. The PVC resin consists of a first PVC resin and a second PVC resin in a mass ratio of 2:1. Extrude (120°C) the foamed layer premix onto the fabric base layer to obtain a foamed layer. 100 parts of second PVC resin, 30 parts of calcium carbonate, 30 parts of dioctyl phthalate, 1 part of stabilizer, 0.1 part of oxidized polyethylene wax, 1 part of stearic acid, 1 part of antimony trioxide, 0.3 parts of antioxidant 619, and 0.3 parts of UV-531 are mixed at 80℃ to obtain a surface layer premix; the surface layer premix is ​​extruded (120℃) and calendered onto the foam layer to obtain a semi-finished product; S2. The surface of the semi-finished product is treated with a treatment agent and then embossed. After inspection, the leather for car seats is obtained.

[0033] Example 2 A manufacturing process for automotive seat leather includes the following steps: S1. Mix 100 parts of PVC resin, 40 parts of calcium carbonate, 50 parts of dioctyl phthalate, 4.5 parts of foaming agent, 6.8 parts of additives, and 4 parts of carbon black at 85°C to obtain a foamed layer premix. The additives consist of the following components by weight: 3 parts of stabilizer, 0.2 parts of oxidized polyethylene wax, 1.2 parts of stearic acid, 2 parts of antimony trioxide, 0.4 parts of antioxidant 619, and 0.4 parts of UV-531. The PVC resin consists of a first PVC resin and a second PVC resin in a mass ratio of 2:1. Extrude (160°C) the foamed layer premix onto the fabric base layer to obtain a foamed layer. 100 parts of second PVC resin, 40 parts of calcium carbonate, 50 parts of dioctyl phthalate, 3 parts of stabilizer, 0.3 parts of oxidized polyethylene wax, 1.2 parts of stearic acid, 2 parts of antimony trioxide, 0.4 parts of antioxidant 619, and 0.4 parts of UV-531 are mixed at 85°C to obtain a surface layer premix; the surface layer premix is ​​extruded (160°C) and calendered onto the foam layer to obtain a semi-finished product; S2. The surface of the semi-finished product is treated with a treatment agent and then embossed. After inspection, the leather for car seats is obtained.

[0034] Example 3 A manufacturing process for automotive seat leather includes the following steps: S1. Mix 100 parts of PVC resin, 50 parts of calcium carbonate, 70 parts of dioctyl phthalate, 6 parts of foaming agent, 10.8 parts of additives, and 5 parts of carbon black at 90°C to obtain a foamed layer premix. The additives consist of the following components by weight: 5 parts of stabilizer, 0.3 parts of oxidized polyethylene wax, 1.5 parts of stearic acid, 3 parts of antimony trioxide, 0.5 parts of antioxidant 619, and 0.5 parts of UV-531. The PVC resin consists of a first PVC resin and a second PVC resin in a mass ratio of 2:1. Extrude (200°C) the foamed layer premix onto a fabric base layer to obtain a foamed layer. S2. Mix 100 parts of the second PVC resin, 50 parts of calcium carbonate, 70 parts of dioctyl phthalate, 5 parts of stabilizer, 0.5 parts of oxidized polyethylene wax, 1.5 parts of stearic acid, 3 parts of antimony trioxide, 0.5 parts of antioxidant 619, and 0.5 parts of UV-531 at 90°C to obtain a surface layer premix; extrude (200°C) the surface layer premix onto the foam layer to obtain a semi-finished product; S2. The surface of the semi-finished product is treated with a treatment agent and then embossed. After inspection, the leather for car seats is obtained.

[0035] Example 4 Compared with Example 2, Example 4 differs in that, in step S1, the PVC resin is composed of a first PVC resin and a second PVC resin in a mass ratio of 7:3.

[0036] Example 5 Compared with Example 4, Example 5 differs in that the second PVC resin (average degree of polymerization of 1470, model PF741, manufacturer SCG Chemicals Public Limited Company) is replaced with an equal amount of PVC resin (average degree of polymerization of 1870, model PG770, manufacturer SCG Chemicals Public Limited Company).

[0037] Example 6 The preparation method of the composite filler includes the following steps: 7.5 parts of N-(2-hydroxypropyl)methacrylamide are dispersed in 500 parts of methanol aqueous solution (the mass ratio of methanol to water is 1:1), 100 parts of calcium carbonate are added, and the mixture is dried after 4 hours to obtain the composite filler; The difference between Example 6 and Example 4 is that the filler is replaced with an equal amount of composite filler prepared by the above preparation method.

[0038] Example 7 The difference between Example 7 and Example 6 is that the amount of N-(2-hydroxypropyl)methacrylamide added is 10 parts.

[0039] Example 8 The difference between Example 8 and Example 7 is that N-(2-hydroxypropyl)methacrylamide is replaced with an equal amount of N-p-hydroxyphenylacrylamide.

[0040] Example 9 The difference between Example 9 and Example 7 is that N-(2-hydroxypropyl)methacrylamide is replaced with an equal amount of N-(hydroxymethyl)acrylamide.

[0041] Example 10 The difference between Example 10 and Example 7 is that N-(2-hydroxypropyl)methacrylamide was replaced with an equal amount of hydroxyacetamide.

[0042] Comparative Example 1 Compared with Example 2, the difference of Comparative Example 1 is that in step S1, the PVC resin is the first PVC resin.

[0043] Comparative Example 2 Compared with Example 2, the difference of Comparative Example 2 is that in step S1, the PVC resin is a second PVC resin.

[0044] Experimental Example 1 For the automotive seat leathers prepared in Examples 1-5 and Comparative Examples 1-2, the tensile load of the specimens was tested according to the test methods specified in GB / T 8948-2008. The specimens were plain weave fabric with a thickness of 1 mm.

[0045] The test results are shown in Table 1: Table 1. Performance test results of automotive seat leather prepared in Examples 1-5 and Comparative Examples 1-2

[0046] As shown in Table 1, when the PVC resin is composed of a first PVC resin and a second PVC resin with different average degrees of polymerization, the strength of the leather for car seats can be improved.

[0047] Experiment Example 2 The tear load of the automotive seat leathers prepared in Examples 4 and 6-10 was tested according to the test methods specified in GB / T 8948-2008.

[0048] The test results are shown in Table 2: Table 2 Performance test results of automotive seat leather prepared in Examples 4 and 6-10

[0049] As shown in Table 2, when composite fillers composed of N-substituted acrylamide compounds containing hydroxyl groups are added as raw materials, the tear strength of leather for automotive seats can be improved.

[0050] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A type of leather for automobile seats, comprising, from bottom to top, a fabric base layer, a foam layer, and a surface layer, characterized in that, The foamed layer comprises the following raw materials in parts by weight: 100 parts of PVC resin, 30-50 parts of filler, 30-70 parts of plasticizer, 3-6 parts of foaming agent, 3.7-10.8 parts of additives, and 3-5 parts of colorant. The PVC resin is composed of a first PVC resin and a second PVC resin, and the average degree of polymerization of the first PVC resin and the second PVC resin is different.

2. The leather for automobile seats according to claim 1, characterized in that, The first PVC resin has an average degree of polymerization of 1135, and the second PVC resin has an average degree of polymerization of 1470.

3. The leather for automobile seats according to claim 1, characterized in that, The mass ratio of the first PVC resin to the second PVC resin is 6~7:

3.

4. The leather for automobile seats according to claim 1, characterized in that, The filler includes one or more of calcium carbonate, talc, and kaolin. The plasticizer includes one or more of dioctyl phthalate, dibutyl phthalate, and diisononyl phthalate; The additives comprise the following components by weight: 1-5 parts stabilizer, 0.1-0.3 parts oxidized polyethylene wax, 1-1.5 parts stearic acid, 1-3 parts antimony trioxide, 0.3-0.5 parts antioxidant, and 0.3-0.5 parts ultraviolet absorber; The foaming agent is a microsphere foaming agent; The colorant includes one or more of carbon black, phthalocyanine blue, and phthalocyanine green.

5. The leather for automobile seats according to claim 1, characterized in that, The filler is a composite filler, and the preparation method of the composite filler includes the following steps: dispersing a hydroxyl-containing N-substituted acrylamide compound in a solution, adding the filler, mixing and drying to obtain the composite filler.

6. The leather for automobile seats according to claim 5, characterized in that, The mass ratio of the filler to the hydroxyl-containing N-substituted acrylamide compound is 20:1.5~2.

7. The leather for automobile seats according to claim 5, characterized in that, The hydroxyl-containing N-substituted acrylamide compounds include one or more of N-(2-hydroxypropyl)methacrylamide, N-p-hydroxyphenylacrylamide, and N-(hydroxymethyl)acrylamide.

8. The leather for automobile seats according to claim 1, characterized in that, The material of the base layer includes one of knitted fabric, non-woven fabric, and artificial leather.

9. The leather for automobile seats according to claim 1, characterized in that, The surface layer comprises the following raw materials in parts by weight: 100 parts of second PVC resin, 30-50 parts of calcium carbonate, 30-70 parts of dioctyl phthalate, 1-5 parts of stabilizer, 0.1-0.5 parts of oxidized polyethylene wax, 1-1.5 parts of stearic acid, 1-3 parts of antimony trioxide, 0.3-0.5 parts of antioxidant, and 0.3-0.5 parts of ultraviolet absorber.

10. A process for preparing automotive seat leather, used to prepare the automotive seat leather according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Mix the foaming layer raw materials to obtain a foaming layer premix; calender the foaming layer premix onto the fabric base layer to obtain a foaming layer; mix the surface layer raw materials to obtain a surface layer premix; calender the surface layer premix onto the foaming layer to obtain a semi-finished product. S2. The surface of the semi-finished product is treated with a treatment agent and then embossed. After inspection, the leather for car seats is obtained.

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