Soft synthetic leather and preparation method thereof

Abstract

The invention relates to soft synthetic leather which comprises a base cloth layer, a wet base and a dry veneering layer, the dry veneering layer is composed of a dry inner layer and a dry outer layer, the dry inner layer is attached to the wet base, the dry outer layer is arranged on the outer surface of the dry veneering layer, the softness of the dry inner layer is larger than that of the dry outer layer, and the dry outer layer is attached to the wet base. The thickness of the dry-method inner layer is larger than that of the dry-method outer layer. The soft synthetic leather is soft in hand feeling, strong in meat texture and good in strength, is a synthetic leather material with low price and high quality, and can be applied to the field of decorative materials such as clothing leather and luggage leather.

Description

[0001] This application is a divisional application. The application number of the parent application is 202210522684.6, the application date is May 13, 2022, and the name of the invention is “Soft synthetic leather and its preparation method”. Technical Field

[0002] The invention relates to the technical field of synthetic leather production, in particular to soft synthetic leather and a method for preparing the soft synthetic leather. Background Art

[0003] Due to the limited natural resources of soft genuine leather and its high price, it cannot meet the growing market demand, and synthetic leather has the problem of insufficient softness. In order to improve the soft feel of synthetic leather, existing tanning factories usually use a rubbing process, and the softener penetrates the micropores of the leather base to soften it. Since the dry surface layer is a non-porous and dense structure, the softener cannot penetrate the dry surface layer, so the dry surface layer feels hard, resulting in the leather surface not being soft enough and the surface touch being poor. The softness of the surface layer of the leather is the most critical, which reflects the tenderness of the skin. The first touch feeling of the hand is very important, and the grade of the leather is often judged based on this. Summary of the invention

[0004] In view of the deficiencies in the prior art, the object of the present invention is to provide a soft synthetic leather with a fresh and tender skin feel.

[0005] The present invention is completed by adopting the following technical scheme: a soft synthetic leather, including a base fabric, a wet-fabric base and a dry-fabricated veneer, wherein the dry-fabricated veneer is composed of a dry-fabricated inner layer and a dry-fabricated outer layer, the dry-fabricated inner layer is bonded to the wet-fabricated base, the outer surface of the dry-fabricated veneer is the dry-fabricated outer layer, the softness of the dry-fabricated inner layer is greater than the softness of the dry-fabricated outer layer, and the thickness of the dry-fabricated inner layer is greater than the thickness of the dry-fabricated outer layer.

[0006] Furthermore, the thickness of the bottom of the texture concave of the dry outer layer is less than 0.02 mm.

[0007] Furthermore, the dry outer layer is made of a dry outer layer mixed liquid coated on a release paper, and the dry inner layer is made of a dry inner layer mixed liquid coated on the dry outer layer.

[0008] Furthermore, the viscosity of the dry outer layer mixed liquid is lower than that of the dry inner layer mixed liquid, and the polyurethane resin content of the dry outer layer mixed liquid is lower than that of the dry inner layer mixed liquid.

[0009] Furthermore, the dry outer layer mixed liquid comprises an outer layer dry polyurethane resin, N,N-dimethylformamide and color powder, the dry inner layer mixed liquid comprises an inner layer dry polyurethane resin, N,N-dimethylformamide and color powder, and the modulus of the inner layer dry polyurethane resin is less than 20kgf / cm 2 The modulus of the outer layer dry polyurethane resin is greater than 45kgf / cm 2 .

[0010] Furthermore, the dry outer layer mixed liquid includes dry silicone polyurethane, N, N-dimethylformamide and color powder, the dry inner layer mixed liquid includes inner layer dry polyurethane resin, N, N-dimethylformamide and color powder, and the modulus of the inner layer dry polyurethane resin is less than 20kgf / cm 2 The modulus of the outer layer of dry silicone polyurethane is greater than 45kgf / cm 2 .

[0011] Furthermore, the dry outer layer mixed liquid includes dry silicone polyurethane, outer layer dry polyurethane resin, N, N-dimethylformamide, and color powder, the dry inner layer mixed liquid includes inner layer dry polyurethane resin, N, N-dimethylformamide and color powder, and the modulus of the inner layer dry polyurethane resin is less than 20kgf / cm 2 The modulus of the dry polyurethane resin of the outer layer is greater than 45kgf / cm 2 The modulus of the dry silicone polyurethane of the outer layer is greater than 45kgf / cm 2 .

[0012] Furthermore, the weight ratio of the dry-process organosilicon polyurethane in the dry-process outer layer mixed liquid to the outer layer dry-process polyurethane resin is 8:40-150.

[0013] Furthermore, the method for preparing the soft synthetic leather comprises a preparation process of a base fabric, a preparation process of a wet-process base and a preparation process of a dry-process veneer, wherein the steps of the dry-process veneer process are as follows:

[0014] (1) Preparation of dry mixed liquid, the dry mixed liquid includes a dry outer mixed liquid and a dry inner mixed liquid,

[0015] a) The dry outer layer mixed liquid is prepared by mixing and stirring the high modulus dry polyurethane resin, N,N-dimethylformamide, polyether modified silicone and color powder, and degassing;

[0016] b) The dry inner layer mixed liquid is composed of low modulus dry polyurethane resin, N,N-dimethylformamide, polyether modified silicone and color powder, mixed and stirred evenly, and degassed;

[0017] (2) Dry veneering, including the following steps:

[0018] a) Preparation of release paper coating: zero-gap coating the dry outer layer mixed solution prepared in step 1a on the release paper film, drying it in an oven until it is semi-dry, and then coating the dry inner layer mixed solution prepared in step 1b, drying it in an oven until it is semi-dry, to obtain a release paper coating;

[0019] b) Dry veneer: firstly, the wet-fabric leather is laminated on the release paper coating by pressure, then dried in an oven, cooled by cooling rollers, and then the release paper and the laminated wet-fabric leather are rolled up separately to obtain the finished leather.

[0020] Furthermore, the dry inner layer is composed of a dry middle layer and a dry inner layer, the dry inner layer is laminated with the wet base, the outer surface of the dry laminate is the dry outer layer, the dry middle layer is between the dry inner layer and the dry outer layer, the dry outer layer and the dry middle layer are both colorless and transparent, and the dry inner layer is colored. The softness of the dry inner layer and the dry middle layer is greater than the softness of the dry outer layer, the thickness of the dry inner layer is greater than the thickness of the dry outer layer, and the thickness of the dry middle layer is greater than the thickness of the dry outer layer.

[0021] Furthermore, the method for preparing the soft synthetic leather comprises a preparation process of a base fabric, a preparation process of a wet-process base and a preparation process of a dry-process veneer, wherein the steps of the dry-process veneer process are as follows:

[0022] (1) Preparation of dry mixed liquid, the dry mixed liquid includes dry outer mixed liquid, dry middle mixed liquid and dry inner mixed liquid,

[0023] a) The dry outer layer mixed liquid is prepared by mixing and evenly stirring a colorless and transparent high modulus dry polyurethane resin, N,N-dimethylformamide, polyether-modified silicone and color powder, and degassing;

[0024] b) The dry middle layer mixed liquid is prepared by mixing and stirring a colorless and transparent low modulus dry polyurethane resin, N,N-dimethylformamide, polyether modified silicone and color powder, and degassing;

[0025] c) The dry inner layer mixture is prepared by mixing and stirring the colored low modulus dry polyurethane resin, N,N-dimethylformamide, polyether modified silicone and color powder, and degassing;

[0026] (2) Dry veneering, including the following steps:

[0027] a) Preparation of release paper coating: zero-gap coating of the dry outer layer mixture prepared in step 1a on the release paper film, drying in an oven until semi-dry, then coating the dry middle layer mixture prepared in step 1b, drying in an oven until semi-dry, and finally coating the dry inner layer mixture prepared in step 1c, drying in an oven until semi-dry, to obtain a release paper coating;

[0028] b) Dry veneer: firstly, the wet-fabric leather is laminated on the release paper coating by pressure, then dried in an oven, cooled by cooling rollers, and then the release paper and the laminated wet-fabric leather are rolled up separately to obtain the finished leather.

[0029] Furthermore, the wet-fabric base includes polyurethane resin, silicone and filler, and silicone is attached to the fiber micropores of the filler, the micropores and gaps inside the polyurethane resin; the weight ratio of polyurethane resin to silicone in the wet-fabric base is 30:0.5-3.8; the silicone is one or two of amino silicone oil and amino polyether block silicone oil.

[0030] Furthermore, the wet-process base is prepared from a wet-process mixture coated on a base fabric, wherein the wet-process mixture includes a polyurethane resin solvent liquid, a softener, N,N-dimethylformamide and a filler, wherein the softener includes silicone or a silicone softener containing silicone. The ion type of the softener is a cation, and the pH value of the silicone softener is less than 5. The silicone softener is an amino silicone oil emulsion or an amino polyether block silicone oil emulsion or an amino polyether block silicone oil solvent liquid or an amino polyether block silicone oil.

[0031] Furthermore, the manufacturing process of the soft synthetic leather comprises the following steps:

[0032] 1. Preparation of mixed liquid, including preparation of wet mixed liquid and dry mixed liquid.

[0033] 1) Preparation of wet mixed liquid: First, mix and stir the soft silicone emulsion, N,N-dimethylformamide, filler, color paste and other raw materials evenly, then add the polyurethane resin solvent liquid, mix and stir evenly, and degas.

[0034] 2) The steps for preparing the dry mixed solution are as follows:

[0035] A. Preparation of dry outer layer mixture: high modulus dry polyurethane resin, N, N-dimethylformamide, butanone, polyether modified silicone and color powder are mixed and stirred evenly, and degassed;

[0036] b. Preparation of dry inner layer mixed liquid: low modulus dry polyurethane resin, N, N-dimethylformamide, butanone, polyether modified silicone and color powder are mixed and stirred evenly, and defoamed.

[0037] 2. Preparation of wet bass:

[0038] 1) Pretreatment of base fabric: immerse the base fabric in an aqueous solution of N,N-dimethylformamide with a concentration of 15-25%, press out the excess aqueous solution with a squeeze roller, and iron it with an ironing wheel, with a humidity of 40%.

[0039] 2) Coating and solidification: The wet mixed liquid is evenly coated on the pretreated base fabric, and then immersed in a solidification tank with a 20% N, N-dimethylformamide aqueous solution for solidification.

[0040] 3) Washing and drying: After complete solidification, it passes through the squeezing rollers to squeeze out the excess coagulation liquid, and then is washed with clean water in a washing tank. The first section of the washing tank is washed with five groups of squeezing rollers, and the second section is washed with six groups of squeezing rollers. Finally, it is dried, expanded, and shaped to obtain the wet-fabricated bass.

[0041] 3. Dry veneer, including the following steps:

[0042] 1) Preparation of release paper coating: zero-gap coating of 2) a dry mixed solution is carried out on the release paper film, and the mixture is dried in an oven until it is semi-dry. Then, 2) b dry mixed solution is coated on the film, and the mixture is dried in an oven until it is semi-dry to obtain a release paper coating.

[0043] 2) Dry veneer: directly laminate the wet-fabric leather onto the release paper coating prepared in step 3) by pressure, then dry it in an oven, cool it with a cooling roller, and then roll up the release paper and the laminated wet-fabric leather separately to obtain the finished leather.

[0044] 4. Finished leather surface coating: The front of the finished leather is coated with a coating agent using three-plate printing, and then dried in an oven to obtain finished leather with a coated effect.

[0045] 5. Finished leather rubbing treatment includes the following steps:

[0046] 1) Add the softener into the water tank and mix well;

[0047] 2) The finished leather is immersed in the aqueous solution in the water tank, then dehydrated and squeezed, and then passed through the rubbing machine to rub and dry;

[0048] 3) After the final inspection, winding and packaging, you will get a synthetic leather material that is soft to the touch, has a strong texture, is strong, and is inexpensive and good value for money.

[0049] The beneficial effects achieved by the present invention are as follows: 1. In the present invention, a multiple coating process is adopted to implement a zero-gap coating process on the release paper film, so as to achieve the thinnest dry outer layer with a higher polyurethane resin modulus, maximize the thickness ratio of the dry inner layer with a lower polyurethane resin modulus to the dry veneer, minimize the polyurethane resin modulus of the dry inner layer, and achieve the best soft hand feeling effect; the current dry one-time coating process can only reduce the dry polyurethane resin modulus to achieve the soft hand feeling effect, and the dry polyurethane resin with too low modulus is relatively sticky after coating and drying, and it is easy for leather to stick to leather or other items, so in order to avoid leather sticking, the soft hand feeling can only be sacrificed;

[0050] 2. In the present invention, the dry-process inner layer adopts a dry-process polyurethane resin with a lower modulus, and the outer layer adopts a dry-process polyurethane resin with a higher modulus, which not only creates leather with a soft feel and a fresh skin feel, but also ensures that the leather surface is dry and non-sticky, and the leather will not stick to each other; the outermost layer adopts a dry-process polyurethane resin with a higher modulus, which helps to resist scratching and abrasion on the leather surface; the current dry-process one-time coating process cannot select a high-modulus dry-process polyurethane resin in order to take into account the softness of the leather, resulting in poor scratch resistance and poor abrasion resistance on the leather surface. In order to resist scratching and abrasion, a layer of scratch-resistant and abrasion-resistant coating needs to be printed, and adding a process requires additional material costs, drying electricity costs, labor costs and losses.

[0051] 3. Dry polyurethane resin with lower modulus is easy to stick to the release paper, making it difficult to peel off and affecting the service life of the release paper. On the contrary, dry polyurethane resin with higher modulus is easy to peel off from the release paper, which increases the service life of the release paper.

[0052] 4. The viscosity of the dry outer layer mixture is relatively low, and it is easy to flow on the release paper with deeper texture. The texture produced is clear and in place, which is conducive to the manufacture of deep-grained leather; the polyurethane resin content of the dry outer layer mixture is lower than that of the dry inner layer mixture, so the thickness of the dry outer layer mixture after drying will be thinner and the feel will be further softer. DETAILED DESCRIPTION

[0053] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation method, structure, characteristics and effects of the present invention are described in detail below in combination with the preferred embodiments.

[0054] The present invention provides a soft synthetic leather, comprising a base fabric layer, a wet base and a dry veneer. The dry veneer layer is composed of a dry inner layer and a dry outer layer, the dry inner layer is attached to the base, and the dry outer layer is away from the outer surface of the base. The softness of the dry inner layer is greater than that of the dry outer layer, and the thickness of the dry inner layer is greater than that of the dry outer layer. The total thickness of the concave bottom of the dry veneer of the clothing leather is generally 0.1-0.15mm. The thickness of the concave bottom of the dry outer layer is less than 0.02mm, and the optimal thickness is 0.01mm. The dry outer layer is made of a dry outer layer mixed liquid coated on a release paper, and the dry inner layer is made of a dry inner layer mixed liquid coated on a dry outer layer. The release paper is preferably a release paper with a special matte and high velvety feel, the dry inner layer is selected from a thick and soft material, and the dry outer layer is selected from a thin and relatively hard material, so that a soft feel is achieved and the leather is guaranteed not to stick.

[0055] Embodiment 1: The dry outer layer mixed liquid in the above-mentioned soft synthetic leather is prepared from the outer layer dry polyurethane resin, N, N-dimethylformamide and color powder. The dry inner layer mixed liquid includes the inner layer dry polyurethane resin, N, N-dimethylformamide and color powder. The modulus of the inner layer dry polyurethane resin is less than 20kgf / cm 2 The optimal modulus of the inner layer dry polyurethane resin is 10kgf / cm 2 The modulus of the outer layer dry polyurethane resin is greater than 45kgf / cm 2 The optimal modulus of the dry polyurethane resin of the outer layer is 80kgf / cm 2 The solid contents of the inner layer dry-process polyurethane resin and the outer layer dry-process polyurethane resin are both 28-32%, and generally the solid content is 30%.

[0056] The dry outer layer mixed liquid is prepared from the following raw materials in percentage by weight:

[0057] Modulus 80kgf / cm 2 40 parts of dry polyurethane resin,

[0058] 30 parts of N,N-dimethylformamide,

[0059] 21.8 parts of butanone,

[0060] 0.2 parts of leveling agent,

[0061] 8 parts of color powder.

[0062] The dry inner layer mixed liquid is prepared from the following raw materials in percentage by weight:

[0063] Modulus 10kgf / cm 2 40 parts of dry polyurethane resin,

[0064] 30 parts of N,N-dimethylformamide,

[0065] 21.5 parts of butanone,

[0066] 0.2 parts of leveling agent,

[0067] Emulsifier AEO-3 is 0.3 parts,

[0068] 8 parts of color powder.

[0069] At present, the dry polyurethane resin for producing garment leather generally adopts 30kgf / cm 2 In this embodiment, the dry inner layer adopts 10kgf / cm 2 The dry polyurethane resin with high modulus feels very soft and tender; the dry outer layer adopts 80kgf / cm 2The dry polyurethane resin has a high modulus and feels very dry. It has good surface scratch and abrasion resistance, good anti-stick performance, and is easy to demould on the release paper, which can extend the life of the release paper.

[0070] In the present invention, a thick and soft resin is selected for the dry inner layer that is bonded to the base to ensure the soft feel of the synthetic leather, while a thin and non-sticky resin is set for the dry outer layer to ensure that the outer surface of the synthetic leather does not adhere to other parts. The two dry polyurethane resins with different moduli are combined to achieve a soft feel and high anti-stick effect.

[0071] Embodiment 2: The dry outer layer mixed liquid in the above-mentioned soft synthetic leather is prepared from an outer layer dry polyurethane resin, N,N-dimethylformamide and color powder. The viscosity of the dry outer layer mixed liquid is lower than that of the dry inner layer mixed liquid, and the polyurethane resin content of the dry outer layer mixed liquid is lower than that of the dry inner layer mixed liquid. The dry inner layer mixed liquid is prepared from an inner layer dry polyurethane resin, N,N-dimethylformamide and color powder. The modulus of the inner layer dry polyurethane resin is less than 20kgf / cm 2 The optimal modulus of the inner layer dry polyurethane resin is 10kgf / cm 2 The modulus of the outer layer dry polyurethane resin is greater than 45kgf / cm 2 The optimal modulus of the dry polyurethane resin of the outer layer is 80kgf / cm 2 The solid contents of the inner layer dry-process polyurethane resin and the outer layer dry-process polyurethane resin are both 28-32%, and generally the solid content is 30%.

[0072] The dry outer layer mixed liquid is prepared from the following raw materials in percentage by weight:

[0073] Modulus 80kgf / cm 2 30 parts of dry polyurethane resin,

[0074] 35 parts of N,N-dimethylformamide,

[0075] 25.8 parts of butanone,

[0076] 0.2 parts of leveling agent,

[0077] 8 parts of color powder.

[0078] The dry inner layer mixed liquid is prepared from the following raw materials in percentage by weight:

[0079] Modulus 10kgf / cm 2 40 parts of dry polyurethane resin,

[0080] 30 parts of N,N-dimethylformamide,

[0081] 21.5 parts of butanone,

[0082] 0.2 parts of leveling agent,

[0083] Emulsifier AEO-3 is 0.3 parts,

[0084] 8 parts of color powder.

[0085] At present, the viscosity of the dry mixed liquid for producing garment leather is generally about 3000; in this embodiment, the viscosity of the dry outer layer mixed liquid is about 2000, the viscosity of the dry inner layer mixed liquid is about 3000, the polyurethane resin content of the dry outer layer mixed liquid is 9%, and the polyurethane resin content of the dry inner layer mixed liquid is 12%. In this embodiment, the viscosity of the dry outer layer mixed liquid is relatively low, which is conducive to the manufacture of deep-grained leather; the polyurethane resin content of the dry outer layer mixed liquid is low, and the thickness of the dry outer layer will be thinner.

[0086] Embodiment 3: In the above-mentioned soft synthetic leather, the dry outer layer mixed liquid is prepared from dry silicone polyurethane, N, N-dimethylformamide and color powder. The dry inner layer mixed liquid is prepared from inner layer dry polyurethane resin, N, N-dimethylformamide and color powder. The modulus of the inner layer dry polyurethane resin is less than 20kgf / cm 2 The optimal modulus of the inner layer dry polyurethane resin is 10kgf / cm 2 The modulus of the outer layer of dry-process silicone polyurethane is greater than 45kgf / cm 2 The best modulus of the outer layer dry silicone polyurethane is 70kgf / cm 2 The solid content of the inner layer dry-process polyurethane resin is 28-32%, and the general solid content is 30%. The solid content of the outer layer dry-process silicone polyurethane is 28-32%, and the general solid content is 30%.

[0087] The dry outer layer mixed liquid is prepared from the following raw materials in percentage by weight:

[0088] Modulus 70kgf / cm 2 40 parts of dry silicone polyurethane,

[0089] 30 parts of N,N-dimethylformamide,

[0090] 21.8 parts of butanone,

[0091] 0.2 parts of leveling agent,

[0092] 8 parts of color powder.

[0093] The dry-process lining mixture is prepared from the following raw materials in percentage by weight:

[0094] Modulus 10kgf / cm 2 40 parts of dry polyurethane resin,

[0095] 30 parts of N,N-dimethylformamide,

[0096] 21.5 parts of butanone,

[0097] 0.2 parts of leveling agent,

[0098] Emulsifier AEO-3 is 0.3 parts,

[0099] 8 parts of color powder.

[0100] Beneficial effects of this embodiment:

[0101] 1. Polyurethane resin is connected with silicone during the synthesis process, which makes dry silicone polyurethane not only soft and smooth, strong skin feel, deep color and high anti-stick properties, but the cost of silicone polyurethane is more than 3 times that of polyurethane resin. Therefore, the dry inner layer uses soft and thick dry polyurethane resin, and the outer layer uses dry silicone polyurethane, which not only reduces the cost but also ensures the softness and high anti-stick properties of the outer layer of synthetic leather.

[0102] 2. In the process of dry veneering, when the material of the special fog high velvet release paper is polyurethane resin, a silicone leveling agent is added to facilitate demoulding and increase the number of times the release paper is used. However, the amount of silicone leveling agent added cannot exceed 0.3% of the total weight. If excessive addition is added, the leather surface will precipitate silicone leveling agent after a period of time, causing spots and increasing the loss rate. Therefore, the amount of leveling agent needs to be limited while ensuring the quality of the leather. The number of times the release paper is used is generally about 10 times; if the material of the special fog high velvet release paper is silicone polyurethane, the smooth isolation function of silicone polyurethane far exceeds the silicone leveling agent, and the number of times the release paper is used is generally more than 50 times. The special fog high velvet release paper is expensive, and the present invention can greatly reduce the cost.

[0103] 3. The haze and brightness of the suede are particularly prominent, which enhances the visual beauty and improves the touch of the suede, giving it a slightly smooth and soft skin-like feel.

[0104] Embodiment 4: In the above-mentioned soft synthetic leather, the dry outer layer mixed liquid is prepared from dry silicone polyurethane, outer layer dry polyurethane resin, N, N-dimethylformamide, and color powder. The dry inner layer mixed liquid is prepared from inner layer dry polyurethane resin, N, N-dimethylformamide, and color powder. The modulus of the inner layer dry polyurethane resin is less than 20kgf / cm 2 The inner layer dry polyurethane resin preferably has a modulus of 10 kgf / cm 2 The modulus of the dry polyurethane resin of the outer layer is greater than 45 kgf / cm 2 The optimal modulus of the dry polyurethane resin of the outer layer is 80kgf / cm 2The modulus of the dry silicone polyurethane of the outer layer is greater than 45 kgf / cm 2 The optimal modulus of dry silicone polyurethane is 70kgf / cm 2 .

[0105] The weight ratio of the dry-process organosilicon polyurethane in the dry-process outer layer mixed liquid to the outer layer dry-process polyurethane resin is 8:40-150, and the most preferred ratio is 8:100. The solid content of the inner layer dry-process polyurethane resin and the outer layer dry-process polyurethane resin are both 28-32%, and the general solid content is 30%. The solid content of the outer layer dry-process organosilicon polyurethane is 28-32%, and the general solid content is 30%.

[0106] The dry outer layer mixed liquid is prepared from the following raw materials in percentage by weight:

[0107] Modulus 70kgf / cm 2 5 parts of dry silicone polyurethane,

[0108] Modulus 80kgf / cm 2 50 parts of dry polyurethane resin,

[0109] 42 parts of N,N-dimethylformamide,

[0110] Butyl ester 15 parts,

[0111] 8 parts of color powder.

[0112] The dry inner layer mixed liquid is prepared from the following raw materials in percentage by weight:

[0113] Modulus 10kgf / cm 2 30 parts of dry polyurethane resin,

[0114] Modulus 15kgf / cm 2 10 parts of dry polyurethane resin,

[0115] 30 parts of N,N-dimethylformamide,

[0116] 21.5 parts of butanone,

[0117] 0.2 parts of leveling agent,

[0118] Emulsifier AEO-3 is 0.3 parts,

[0119] 8 parts of color powder.

[0120] When the special matte and high-velvet release paper is made of silicone polyurethane and polyurethane resin, the release paper can be used nearly 50 times, which further reduces the cost. Compared with the leather velvet made of polyurethane resin, the matte, brightness, smoothness and skin feel of the release paper are significantly improved.

[0121] In the present invention, the method for preparing the soft synthetic leather comprises a preparation process of a base fabric, a preparation process of a wet-process base and a preparation process of a dry-process veneer, wherein the steps of the preparation process of the dry-process veneer are as follows:

[0122] (1) Preparation of dry mixed liquid. The dry mixed liquid includes a dry outer mixed liquid and a dry inner mixed liquid, which are prepared as follows:

[0123] a) The dry outer layer mixed liquid is prepared by mixing and stirring the high modulus dry polyurethane resin, N,N-dimethylformamide, polyether modified silicone and color powder, and degassing;

[0124] b) The dry inner layer mixed liquid is prepared by mixing low modulus dry polyurethane resin, N,N-dimethylformamide, polyether modified silicone and color powder, and stirring them uniformly and degassing them.

[0125] (2) Dry veneering, including the following steps:

[0126] a) Preparation of release paper coating: zero-gap coating of the dry outer layer mixture prepared in step 1 is performed on the release paper film, and the mixture is dried in an oven until it is semi-dry. Then, the dry inner layer mixture prepared in step 1 is coated on the release paper film, and the mixture is dried in an oven until it is semi-dry to obtain a release paper coating.

[0127] b) Dry veneer: firstly, the wet-fabric leather is laminated on the release paper coating by pressure, then dried in an oven, cooled by cooling rollers, and then the release paper and the laminated wet-fabric leather are rolled up separately to obtain the finished leather.

[0128] In the embodiment of the preparation process of dry veneer, the dry outer layer mixed liquid is coated on the release paper film with zero gap, so that the bottom thickness of the dry outer layer can be less than 0.02mm, the thickness of the dry soft inner layer can be maximized, and the maximum softness can be achieved under the premise of ensuring anti-sticking.

[0129] Embodiment 5: The above-mentioned soft synthetic leather comprises a base fabric layer, a wet base and a dry veneer. The dry veneer layer is composed of a dry inner layer and a dry outer layer, the dry inner layer is composed of a dry middle layer and a dry inner layer, the dry inner layer is bonded to the wet base, the outer surface of the dry veneer is the dry outer layer, the dry middle layer is between the dry inner layer and the dry outer layer, the dry outer layer and the dry middle layer are both colorless and transparent, and the dry inner layer is colored. The softness of the dry inner layer and the dry middle layer is greater than the softness of the dry outer layer, the thickness of the dry inner layer is greater than the thickness of the dry outer layer, and the thickness of the dry middle layer is greater than the thickness of the dry outer layer. The thickness of the dry outer layer is 0.015 mm, the thickness of the dry middle layer is 0.08 mm, and the thickness of the dry outer layer is 0.04 mm.

[0130] The dry outer layer mixed liquid is prepared from a colorless and transparent outer layer dry polyurethane resin and N,N-dimethylformamide. The dry middle layer mixed liquid includes a colorless and transparent middle layer dry polyurethane resin and N,N-dimethylformamide. The dry inner layer mixed liquid includes an inner layer dry polyurethane resin, N,N-dimethylformamide, and color powder. The modulus of the dry polyurethane resin of the middle layer and the inner layer is less than 20kgf / cm 2 The optimum modulus of the dry polyurethane resin in the middle and inner layers is 10kgf / cm 2 The modulus of the outer layer dry polyurethane resin is greater than 45kgf / cm 2 The optimal modulus of the dry polyurethane resin of the outer layer is 80kgf / cm 2 The solid content of the dry-process polyurethane resin of the inner layer, the middle layer and the outer layer is 28-32%, and the general solid content is 30%.

[0131] The dry outer layer mixed liquid is prepared from the following raw materials in percentage by weight:

[0132] Modulus 80kgf / cm 2 40 parts of colorless and transparent dry polyurethane resin,

[0133] 38 parts of N,N-dimethylformamide,

[0134] 21.8 parts of butanone,

[0135] 0.2 parts of leveling agent.

[0136] The dry middle layer mixed liquid is prepared from the following raw materials in percentage by weight:

[0137] Modulus 10kgf / cm 2 40 parts of colorless and transparent dry polyurethane resin,

[0138] 38 parts of N,N-dimethylformamide,

[0139] 21.5 parts of butanone,

[0140] 0.2 parts of leveling agent,

[0141] The emulsifier AEO-3 is 0.3 parts.

[0142] The dry-process lining mixture is prepared from the following raw materials in percentage by weight:

[0143] Modulus 10kgf / cm 2 40 parts of dry polyurethane resin,

[0144] 30 parts of N,N-dimethylformamide,

[0145] 21.5 parts of butanone,

[0146] 0.2 parts of leveling agent,

[0147] Emulsifier AEO-3 is 0.3 parts,

[0148] 8 parts of color powder.

[0149] The steps of dry veneering process are as follows:

[0150] (1) Preparation of dry mixed liquid, the dry mixed liquid includes dry outer mixed liquid, dry middle mixed liquid and dry inner mixed liquid,

[0151] a) The dry outer layer mixed liquid is prepared by mixing and evenly stirring a colorless and transparent high modulus dry polyurethane resin, N,N-dimethylformamide, polyether-modified silicone and color powder, and degassing;

[0152] b) The dry middle layer mixed liquid is prepared by mixing and stirring a colorless and transparent low modulus dry polyurethane resin, N,N-dimethylformamide, polyether modified silicone and color powder, and degassing;

[0153] c) The dry inner layer mixture is prepared by mixing and stirring the colored low modulus dry polyurethane resin, N,N-dimethylformamide, polyether modified silicone and color powder, and degassing;

[0154] (2) Dry veneering, including the following steps:

[0155] a) Preparation of release paper coating: zero-gap coating of the dry outer layer mixture prepared in step 1a on the release paper film, drying in an oven until semi-dry, then coating the dry middle layer mixture prepared in step 1b, drying in an oven until semi-dry, and finally coating the dry inner layer mixture prepared in step 1c, drying in an oven until semi-dry, to obtain a release paper coating;

[0156] b) Dry veneer: firstly, the wet-fabric leather is laminated on the release paper coating by pressure, then dried in an oven, cooled by cooling rollers, and then the release paper and the laminated wet-fabric leather are rolled up separately to obtain the finished leather.

[0157] Beneficial effects of this embodiment: Since the outer layer and the middle layer are colorless and transparent, and the inner layer is colored, the leather texture produced has a crystal clear visual effect, and has soft hand feel, anti-sticking, anti-scratch, anti-wear and other effects. It is suitable for producing some leathers with special visual effects such as pearl texture, thick texture, full texture, etc., providing some new leather products and achieving high added value.

[0158] Embodiment 6: In the above-mentioned soft synthetic leather, the dry veneer comprises a dry inner layer and a dry outer layer, the dry inner layer is bonded to the wet base, the outer surface of the dry veneer is the dry outer layer, the softness of the dry inner layer is greater than the softness of the dry outer layer, and the thickness of the dry inner layer is greater than the thickness of the dry outer layer. The thickness of the concave bottom of the dry outer layer is less than 0.02mm, and the optimal thickness is 0.015mm; the wet base includes polyurethane resin, silicone and filler, silicone is attached to the fiber micropores of the filler, the micropores and gaps inside the polyurethane resin, and the inner wall of the pores formed when the fiber of the filler shrinks is also attached to silicone; the weight ratio of polyurethane resin to silicone in the wet base is 30:0.5-3.8, and the most preferred ratio is 30:1.5. The silicone is one or two of amino silicone oil and amino polyether block silicone oil.

[0159] The preparation of soft synthetic leather includes the preparation of wet base and the preparation of dry veneer.

[0160] The dry outer layer mixed liquid is prepared from an outer layer dry polyurethane resin, N, N-dimethylformamide and color powder. The dry inner layer mixed liquid is prepared from an inner layer dry polyurethane resin, N, N-dimethylformamide and color powder. The modulus of the inner layer dry polyurethane resin is less than 20kgf / cm 2 The optimal modulus of the inner layer dry polyurethane resin is 10kgf / cm 2 The modulus of the outer layer dry polyurethane resin is greater than 45kgf / cm 2 The optimal modulus of the dry polyurethane resin of the outer layer is 80kgf / cm 2 The solid contents of the inner layer dry-process polyurethane resin and the outer layer dry-process polyurethane resin are both 28-32%, and generally the solid content is 30%.

[0161] Wet-fabricated base is prepared by a wet-fabricated mixture coated on a base fabric, wherein the wet-fabricated mixture includes a polyurethane resin solvent liquid, an amino polyether block silicone oil emulsion, N,N-dimethylformamide and a filler; the amino polyether block silicone oil emulsion is a cationic liquid with a pH value of less than 5, and an optimal pH value of 2.2; the solid content of the polyurethane resin solvent liquid is 28-32%, and the general solid content is 30%.

[0162] The dry outer layer mixed liquid is prepared from the following raw materials in percentage by weight:

[0163] Modulus 80kgf / cm 2 40 parts of dry polyurethane resin,

[0164] 30 parts of N,N-dimethylformamide,

[0165] 21.8 parts of butanone,

[0166] 0.2 parts of leveling agent,

[0167] 8 parts of color powder.

[0168] The dry inner layer mixed liquid is prepared from the following raw materials in percentage by weight:

[0169] Modulus 10kgf / cm 2 40 parts of dry polyurethane resin,

[0170] 30 parts of N,N-dimethylformamide,

[0171] 21.5 parts of butanone,

[0172] 0.2 parts of leveling agent,

[0173] Emulsifier AEO-3 is 0.3 parts,

[0174] 8 parts of color powder.

[0175] The wet mixture is prepared from the following raw materials in percentage by weight:

[0176] Modulus 5kgf / cm 2 27 parts of wet polyurethane resin solvent liquid,

[0177] Modulus 10kgf / cm 2 12 parts of wet polyurethane resin solvent liquid,

[0178] 3 parts of cationic silicone emulsion,

[0179] 46 parts of N,N-dimethylformamide,

[0180] 12 parts of wood fiber powder.

[0181] Furthermore, the manufacturing process of the soft synthetic leather comprises the following steps:

[0182] 1. Preparation of mixed liquid, including preparation of wet mixed liquid and dry mixed liquid.

[0183] 1) Preparation of wet mixed liquid: First, mix and stir the soft silicone emulsion, N,N-dimethylformamide, filler, color paste and other raw materials evenly, then add the polyurethane resin solvent liquid, mix and stir evenly, and degas.

[0184] 2) The steps for preparing the dry mixed solution are as follows:

[0185] A. Preparation of dry outer layer mixture: high modulus dry polyurethane resin, N, N-dimethylformamide, butanone, polyether modified silicone and color powder are mixed and stirred evenly, and degassed;

[0186] b. Preparation of dry inner layer mixed liquid: low modulus dry polyurethane resin, N, N-dimethylformamide, butanone, polyether modified silicone and color powder are mixed and stirred evenly, and defoamed.

[0187] 2. Preparation of wet bass:

[0188] 1) Pretreatment of base fabric: immerse the base fabric in an aqueous solution of N,N-dimethylformamide with a concentration of 15-25%, press out the excess aqueous solution with a squeeze roller, and iron it with an ironing wheel, with a humidity of 40%.

[0189] 2) Coating and solidification: The wet mixed liquid is evenly coated on the pretreated base fabric, and then immersed in a solidification tank with a 20% N, N-dimethylformamide aqueous solution for solidification.

[0190] 3) Washing and drying: After complete solidification, it passes through the squeezing rollers to squeeze out the excess coagulation liquid, and then is washed with clean water in a washing tank. The first section of the washing tank is washed with five groups of squeezing rollers, and the second section is washed with six groups of squeezing rollers. Finally, it is dried, expanded, and shaped to obtain the wet-fabricated bass.

[0191] 3. Dry veneer, including the following steps:

[0192] 1) Preparation of release paper coating: zero-gap coating of 2) a dry mixed solution is carried out on the release paper film, and the mixture is dried in an oven until it is semi-dry. Then, 2) b dry mixed solution is coated on the film, and the mixture is dried in an oven until it is semi-dry to obtain a release paper coating.

[0193] 2) Dry veneer: directly laminate the wet-fabric leather onto the release paper coating prepared in step 3) by pressure, then dry it in an oven, cool it with a cooling roller, and then roll up the release paper and the laminated wet-fabric leather separately to obtain the finished leather.

[0194] 4. Finished leather rubbing treatment includes the following steps:

[0195] 1) Add the softener into the water tank and mix well;

[0196] 2) The finished leather is immersed in the aqueous solution in the water tank, then dehydrated and squeezed, and then passed through the rubbing machine to rub and dry;

[0197] 3) After the final inspection, winding and packaging, you will get a synthetic leather material that is soft to the touch, has a strong texture, is strong and inexpensive.

[0198] The pores and gaps in the bass are attached with soft silicone to lubricate and reduce the friction coefficient, making it soft and comfortable to touch. The soft silicone emulsion plays a role of uniform dispersion in the wet mixture, so that the filler wood fiber powder is evenly dispersed. After the wet mixture is coated, it is washed and dried in the coagulation tank. After the filler wood fiber powder shrinks, it forms a uniformly distributed pore structure, and it feels strong to touch. At the same time, the soft silicone emulsion is wrapped by the polyurethane resin solvent liquid. After the wet mixture is coated, it is washed and dried in the coagulation tank, and very dense micropores containing soft silicone are formed in the resin, making the bass particularly soft. The soft silicone is adsorbed between the pores and fibers of the filler wood fiber powder, making the filler soft. The soft silicone is basically adsorbed in the pores and gaps of the bass. The soft silicone is rarely taken away by water during the coagulation tank washing process. Since the soft silicone is a liquid, the solvent recovery system is not easy to be blocked. Since wet-fabricated base relies on the softening effect of soft silicone, the cells do not need to be overly dense, so it has good firmness, peel strength and tear strength.

[0199] In addition, multiple coating processes are adopted to implement zero-gap coating on the release paper film, so as to achieve the thinnest dry outer layer with higher polyurethane resin modulus, maximize the thickness ratio of the dry inner layer with lower polyurethane resin modulus, minimize the polyurethane resin modulus of the dry inner layer, and achieve the best soft feel.

[0200] This embodiment achieves the ultimate softness of both the base and the veneer, and the leather surface is anti-stick, scratch-resistant and wear-resistant, so that the quality of synthetic leather exceeds that of genuine leather, realizes the high-end status of synthetic leather, and greatly improves the added value of the product.

[0201] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A soft synthetic leather, comprising a base fabric, a wet-process base and a dry-process veneer, characterized in that: The dry veneer comprises a dry inner layer and a dry outer layer, the dry inner layer is bonded to the wet base, the outer surface of the dry veneer is the dry outer layer, the softness of the dry inner layer is greater than the softness of the dry outer layer, the thickness of the dry inner layer is greater than the thickness of the dry outer layer; the thickness of the concave bottom of the dry outer layer is less than 0.02mm; The raw materials of the dry outer layer mixed liquid include outer layer dry polyurethane resin, N, N-dimethylformamide and color powder, the raw materials of the dry inner layer mixed liquid include inner layer dry polyurethane resin, N, N-dimethylformamide and color powder, and the modulus of the inner layer dry polyurethane resin is less than 20kgf / cm 2 The modulus of the outer layer dry polyurethane resin is greater than 45kgf / cm 2 .

2. The soft synthetic leather according to claim 1, characterized in that: The raw material of the dry outer layer includes dry silicone polyurethane, and the weight ratio of the dry silicone polyurethane to the outer layer dry polyurethane resin in the dry outer layer mixed liquid is 8:40-150.

3. The soft synthetic leather according to claim 1 or 2, characterized in that: The wet-fabric base includes polyurethane resin, silicone and filler, wherein the weight ratio of polyurethane resin to silicone in the wet-fabric base is 30:0.5-3.8; the silicone is one or two of amino silicone oil and amino polyether block silicone oil.

4. The soft synthetic leather according to any one of claims 1 to 3, characterized in that: The dry outer layer is made of a dry outer layer mixed liquid coated on the release paper, and the dry inner layer is made of a dry inner layer mixed liquid coated on the dry outer layer.

5. The soft synthetic leather according to claim 4, characterized in that: The viscosity of the dry outer layer mixed liquid is lower than that of the dry inner layer mixed liquid, and the polyurethane resin content of the dry outer layer mixed liquid is lower than that of the dry inner layer mixed liquid.

6. The soft synthetic leather according to claim 3 or 4, characterized in that: The raw materials of the dry outer layer mixed liquid include dry silicone polyurethane, N, N-dimethylformamide and color powder, and the raw materials of the dry inner layer mixed liquid include inner layer dry polyurethane resin, N, N-dimethylformamide and color powder. The modulus of the inner layer dry polyurethane resin is less than 20kgf / cm 2 The modulus of the outer layer of dry silicone polyurethane is greater than 45kgf / cm 2 .

7. The soft synthetic leather according to claim 3 or 4, characterized in that: The raw materials of the dry outer layer mixed liquid include dry silicone polyurethane, outer layer dry polyurethane resin, N, N-dimethylformamide, and color powder. The raw materials of the dry inner layer mixed liquid include inner layer dry polyurethane resin, N, N-dimethylformamide and color powder. The modulus of the inner layer dry polyurethane resin is less than 20kgf / cm 2 The modulus of the dry polyurethane resin of the outer layer is greater than 45kgf / cm 2 The modulus of the dry silicone polyurethane of the outer layer is greater than 45kgf / cm 2 .

8. The method for preparing the soft synthetic leather according to any one of claims 1, 2, 4, 5, 6 or 7, characterized in that: The method includes the preparation of base fabric, the preparation of wet base and the preparation of dry veneer, wherein the preparation steps of dry veneer are as follows: (1) Preparation of dry mixed liquid, the dry mixed liquid includes a dry outer mixed liquid and a dry inner mixed liquid, a) The dry outer layer mixed liquid is prepared by mixing and stirring the high modulus dry polyurethane resin, N,N-dimethylformamide, polyether modified silicone and color powder, and degassing; b) The dry inner layer mixed liquid is mixed and stirred evenly by low modulus dry polyurethane resin, N,N-dimethylformamide, polyether modified silicone and color powder, and degassing; (2) Dry veneering, including the following steps: a) Preparation of release paper coating: zero-gap coating the dry outer layer mixed solution prepared in step 1a on the release paper film, drying it in an oven until it is semi-dry, and then coating the dry inner layer mixed solution prepared in step 1b, drying it in an oven until it is semi-dry, to obtain a release paper coating; b) Dry veneer: firstly, the wet-fabric leather is laminated on the release paper coating by pressure, then dried in an oven, cooled by cooling rollers, and then the release paper and the laminated wet-fabric leather are rolled up separately to obtain the finished leather.

9. The soft synthetic leather according to claim 1 or 2 or 4 or 5 or 6 or 7, characterized in that: The dry inner layer is composed of a dry middle layer and a dry inner layer. The dry inner layer is bonded to the wet base. The outer surface of the dry veneer is the dry outer layer. The dry middle layer is between the dry inner layer and the dry outer layer. The dry outer layer and the dry middle layer are both colorless and transparent, and the dry inner layer is colored. The softness of the dry inner layer and the dry middle layer is greater than the softness of the dry outer layer. The thickness of the dry inner layer is greater than the thickness of the dry outer layer, and the thickness of the dry middle layer is greater than the thickness of the dry outer layer.

10. The soft synthetic leather according to claim 3, characterized in that: Silicone is attached to the fiber micropores of the filler and the micropores and gaps inside the polyurethane resin; the wet-fabric base is prepared by a wet mixture coated on a base fabric, the wet mixture includes a polyurethane resin solvent liquid, a softener, N,N-dimethylformamide and a filler, the softener includes silicone or a silicone softener containing silicone, the ion type of the softener is cationic, the pH value of the silicone softener is less than 5, and the silicone softener is an amino silicone oil emulsion or an amino polyether block silicone oil emulsion or an amino polyether block silicone oil solvent liquid or an amino polyether block silicone oil.