Solvent-free polyurethane stock solution and high-bonding polyurethane resin for synthetic leather

Abstract

The invention relates to a solvent-free polyurethane stock solution and a high-bonding polyurethane resin for synthetic leather, the stock solution comprises a composition A containing bisphenol A modified polyether polyol and epoxy resin, and a composition B containing a polyurethane prepolymer, the polyurethane prepolymer is obtained by carrying out a reaction on bisphenol A modified polyether polyol, polyether polyol and aliphatic polyisocyanate. The high-adhesion polyurethane resin for the synthetic leather is obtained by reacting a composition A and a composition B, wherein the molar ratio of reactive groups to NCO in the composition A to NCO groups in the composition B is (0.98-1.10): 1. The polyurethane resin and synthetic leather prepared from the solvent-free polyurethane stock solution solve the technical problems of poor cohesiveness, peel strength, heat resistance and alcohol resistance of conventional solvent-free aliphatic polyurethane, and have excellent comprehensive performance.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane, and in particular to a solvent-free polyurethane stock solution and a high-bonding polyurethane resin for synthetic leather. Technical Background

[0002] With the popularity of solvent-free polyurethane resins, their applications in the field of synthetic leather are also increasing. At present, solvent-free polyurethane resins for synthetic leather are mainly used as surface materials or middle layer materials of synthetic leather. Polyurethane resins mainly include aromatic polyurethane resins and aliphatic polyurethane resins: although aromatic polyurethane resins have good heat resistance and alcohol resistance, they have poor yellowing resistance and are difficult to meet the requirements of synthetic leather products that need long-term outdoor use; although aliphatic polyurethane resins have good yellowing resistance, they have defects such as poor bonding effect, weak peel strength, poor heat resistance, and inability to alcohol and its solvents. In addition, there is still a certain gap in the comprehensive physical properties of solvent-free polyurethane resins and solvent-based polyurethane resins. Therefore, it is of great significance to develop a solvent-free aliphatic polyurethane stock solution with good heat resistance, strong bonding, alcohol resistance and solvent resistance and its polyurethane resin for synthetic leather. Summary of the invention

[0003] Technical problem: The purpose of the present invention is to overcome the above defects and provide a solvent-free polyurethane stock solution and a high-bonding polyurethane resin for synthetic leather obtained by using the stock solution. The polyurethane resin and synthetic leather prepared by using the solvent-free polyurethane stock solution solve the technical problems of poor adhesion, peel strength, heat resistance and alcohol resistance of conventional solvent-free aliphatic polyurethanes, and have excellent comprehensive performance.

[0004] Technical solution: The solvent-free polyurethane stock solution of the present invention comprises the following components:

[0005] Composition A containing bisphenol A modified polyether polyol and epoxy resin,

[0006] Composition B containing a polyurethane prepolymer,

[0007] in,

[0008] The polyurethane prepolymer is obtained by reacting bisphenol A modified polyether polyol, polyether polyol and aliphatic polyisocyanate.

[0009] The composition A has an OH value of 65 to 205 mgKOH / g.

[0010] The composition B has an NCO content of 8 to 28% by mass.

[0011] The epoxy value of the epoxy resin is 0.3-0.5, and the epoxy resin accounts for 3-5% of the total mass of the composition A.

[0012] The composition A, wherein the mass content of bisphenol A in the bisphenol A modified polyether polyol is 23-75%, and the number average molecular weight is 300-1000.

[0013] The composition A further contains a chain extender and / or polyether polyol.

[0014] The aliphatic polyisocyanate includes one or more of isophorone diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and isomers and / or derivatives and / or modified polymers thereof.

[0015] The polyether polyol is selected from one or more of polyethylene oxide polyol, propylene oxide polyol, ethylene oxide-propylene oxide polyol and polyoxytetramethylene oxide polyol, and has a number average molecular weight of 1000 to 6000.

[0016] The chain extender includes C2-C6 diols, and further includes one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, pentanediol, neopentyl glycol, and hexanediol.

[0017] The invention discloses a high-bonding polyurethane resin for synthetic leather prepared by using the solvent-free polyurethane stock solution. The high-bonding polyurethane resin for synthetic leather is obtained by reacting a composition A and a composition B. The molar ratio of the reactive groups to NCO in the composition A to the NCO groups in the composition B is 0.98-1.10:1.

[0018] Beneficial effects: The solvent-free polyurethane stock solution of the present invention adopts aliphatic polyisocyanate, and solves the technical problems of poor adhesion, peel strength, heat resistance and alcohol resistance of conventional solvent-free aliphatic polyurethane by introducing bisphenol A-modified polyether polyol and epoxy resin. The polyurethane resin and synthetic leather prepared by using the solvent-free polyurethane stock solution have excellent comprehensive properties. DETAILED DESCRIPTION

[0019] The solvent-free polyurethane stock solution comprises the following components:

[0020] A composition A containing at least bisphenol A modified polyether polyol and epoxy resin, and a composition B containing at least polyurethane prepolymer, wherein the polyurethane prepolymer is obtained by reacting bisphenol A modified polyether polyol, polyether polyol and aliphatic polyisocyanate;

[0021] The OH value of the composition A is 65 to 205 mg KOH / g, preferably 68 to 204 mg KOH / g;

[0022] The composition B has an NCO mass content of 8 to 28%;

[0023] The epoxy value of the epoxy resin is 0.3-0.5, and the epoxy resin accounts for 3-5% of the total mass of the composition A;

[0024] In the present invention, the epoxy value is defined as the amount of epoxy group contained in 100g of epoxy resin, in mol / 100g;

[0025] The bisphenol A modified polyether polyol has a bisphenol A mass content of 23-75%, preferably 23-71%, and a number average molecular weight of 300-1000, preferably 320-980;

[0026] The composition A contains at least one of the following components in addition to the bisphenol A modified polyether polyol:

[0027] Chain extenders;

[0028] Polyether polyols;

[0029] In some embodiments of the present invention, the composition A and / or the composition B does not contain polyester polyol;

[0030] In the present invention, the content of the chain extender and polyether polyol can be added according to actual needs;

[0031] As an example, the bisphenol A modified polyether polyol can be prepared by a common preparation method in the art or obtained commercially;

[0032] The preparation method of the bisphenol A modified polyether polyol comprises: reacting bisphenol A with a small molecule alkylene oxide in the presence of a catalyst to obtain the polyether polyol, wherein the small molecule alkylene oxide comprises one or more of ethylene oxide and propylene oxide;

[0033] Commercially available bisphenol A modified polyether polyols include one or more of the brand products HMP-509B, HMP-532B, HMP-536B, HMP-560B, etc. produced by Zhejiang Huangma Technology Co., Ltd., and one or more of the brand products BP-11, BP-33, BP-55, etc. produced by Jiangsu Guodu Co., Ltd.;

[0034] The aliphatic polyisocyanate includes one or more of isophorone diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and isomers and / or derivatives and / or modified polymers thereof.

[0035] The polyether polyol is selected from one or more of polyethylene oxide polyol, propylene oxide polyol, ethylene oxide-propylene oxide polyol, and polyoxytetramethylene oxide polyol, and has a number average molecular weight of 1000 to 6000;

[0036] The chain extender includes C2-C8 diols, and further includes one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, pentanediol, neopentyl glycol, hexanediol, heptanediol, and octanediol;

[0037] The solvent-free polyurethane stock solution may be added with additives commonly used in the art. For example, the additives are added to component A.

[0038] The additives include any one of a catalyst, a foaming agent, a foam leveling agent, and a leveling agent, or a combination of at least two of them;

[0039] As an example, the catalyst includes one or more of an organotin, an organozinc-bismuth combination, and a delayed blocking amine (DBU);

[0040] The foaming agent includes water;

[0041] The foam leveling agent includes one or more of polyether modified silicone oil, L1508, L580, etc.;

[0042] The leveling agent includes one or more of DC-193 and BYK9565;

[0043] As an example, the additive is added to composition A;

[0044] There is no special requirement for the amount of the additive, as long as it does not cause degradation to the resin itself. In some embodiments of the present invention, the additive is less than 3 parts by weight;

[0045] In some examples of the present invention, the composition A comprises 5 to 10 parts by weight of bisphenol A modified polyether polyol and 3 to 5 parts by weight of epoxy resin;

[0046] Preferably, the composition A further comprises 80 to 90 parts by weight of polyether polyol and 3 to 5 parts by weight of chain extender;

[0047] The component B is a polyurethane prepolymer obtained by reacting 20 to 30 parts by weight of polyether polyol, 15 to 20 parts by weight of bisphenol A polyether polyol and 50 to 60 parts by weight of aliphatic polyisocyanate.

[0048] The high-bonding polyurethane resin for synthetic leather is obtained by reacting component A and component B of the stock solution, wherein the molar ratio of the group reactive to NCO in component A to the NCO group in the component is 0.98-1.1:1;

[0049] In some examples of the present invention, the bisphenol A modified polyether polyol accounts for 5-10% of the total mass of the polyurethane resin.

[0050] As an example, the high-bonding synthetic leather polyurethane resin is used as the intermediate layer material of the synthetic leather, and the preparation method of the synthetic leather containing the solvent-free polyurethane resin is as follows:

[0051] The surface layer resin is coated on the release paper with a coating thickness of 0.10-0.15 mm, and the polyurethane resin surface layer material is obtained after drying at 90-120° C. for 2-5 minutes; the solvent-free high-bonding polyurethane resin is uniformly coated on the surface layer resin with a coating thickness of 0.20-0.40 mm, and maintained at 100-120° C. for 60-90 seconds to obtain a semi-cured solvent-free polyurethane middle layer with good adhesion; the base fabric is attached to the semi-cured solvent-free polyurethane middle layer, and after ripening at 120-150° C. for 3-7 minutes, the release paper is separated to obtain the polyurethane synthetic leather.

[0052] The principles and features of the present invention are described below in conjunction with implementation examples. The examples given are for the convenience of those skilled in the art to better understand the present invention. In addition, it should be understood that after reading the contents taught by the present invention, those skilled in the art may make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the claims attached to this application.

[0053] Example 1

[0054] The solvent-free polyurethane stock solution includes the following components:

[0055] Composition A includes 6 parts by weight of bisphenol A modified ethylene oxide-propylene oxide polyether polyol (number average molecular weight of 500, wherein the bisphenol A mass content is about 25%), 4 parts by weight of epoxy resin E44 (epoxy value is about 0.45), 40 parts by weight of polytetramethylene ether polyol (number average molecular weight of 2000), 44.5 parts by weight of polyoxyethylene-propylene oxide ether polyol (number average molecular weight of 2000), and 5 parts by weight of butanediol;

[0056] Composition B comprises 55 parts by weight of dicyclohexylmethane diisocyanate, 17 parts by weight of bisphenol A modified ethylene oxide-propylene oxide polyether polyol (number average molecular weight of 500, wherein the mass content of bisphenol A is about 25%), and 28 parts by weight of polytetramethylene ether polyol (number average molecular weight of 2000) to obtain a polyurethane prepolymer;

[0057] The OH value of composition A is 127 mg KOH / g, and the epoxy resin accounts for 4% of the total mass of composition A; the NCO mass content of composition B is 13.6%.

[0058] Example 2

[0059] The solvent-free polyurethane stock solution includes the following components:

[0060] Composition A includes 8 parts by weight of bisphenol A modified polyoxyethylene-oxypropylene ether polyol (number average molecular weight of 980, wherein the mass content of bisphenol A is about 70%), 3 parts by weight of epoxy resin E44 (epoxy value of about 0.45), 85.3 parts by weight of polyoxyethylene-oxypropylene ether polyol (number average molecular weight of 2000), and 3 parts by weight of ethylene glycol;

[0061] Composition B comprises 52 parts by weight of hexamethylene diisocyanate, 20 parts by weight of bisphenol A modified polyoxyethylene-oxypropylene ether polyol (number average molecular weight of 980, wherein the mass content of bisphenol A is about 70%), and 28 parts by weight of polyoxyethylene-oxypropylene ether polyol (number average molecular weight of 2000) to obtain a polyurethane prepolymer;

[0062] The OH value of composition A is 107 mg KOH / g, and the epoxy resin accounts for 3% of the total mass of composition A; the NCO mass content of composition B is 23.7%.

[0063] Example 3

[0064] The difference between the solvent-free polyurethane stock solution and Example 1 is that an equal molar amount of bisphenol A-modified ethylene oxide-propylene oxide polyether polyol (number average molecular weight of 500, wherein the bisphenol A mass content is about 25%) is used to replace the polytetrahydrofuran ether polyol and polyoxyethylene-propylene oxide ether polyol in composition A, and the rest remains unchanged.

[0065] Example 4

[0066] The solvent-free polyurethane stock solution includes the following components:

[0067] Composition A includes 10 parts by weight of bisphenol A modified polyoxyethylene-oxypropylene ether polyol (number average molecular weight of 980, wherein the mass content of bisphenol A is about 70%), 5 parts by weight of epoxy resin E44 (epoxy value of about 0.45), 80.3 parts by weight of polytetramethylene ether polyol (number average molecular weight of 2000), and 4 parts by weight of butanediol;

[0068] Composition B comprises 52.2 parts by weight of hexamethylene diisocyanate, 18.4 parts by weight of bisphenol A modified polyoxyethylene-oxypropylene ether polyol (number average molecular weight of 980, wherein the mass content of bisphenol A is about 70%), and 29.4 parts by weight of polyoxyethylene-oxypropylene ether polyol (number average molecular weight of 2000) to obtain a polyurethane prepolymer;

[0069] The OH value of composition A is 131 mg KOH / g, and the epoxy resin accounts for 5% of the total mass of composition A; the NCO mass content of composition B is 23.8%.

[0070] Example 5

[0071] The difference between the solvent-free polyurethane stock solution and Example 1 is that the epoxy resin E35 with a relatively low epoxy value content (epoxy value is about less than 0.3) is used to replace the epoxy resin E44.

[0072] Example 6

[0073] The difference between the solvent-free polyurethane stock solution and Example 1 is that the epoxy resin E44 accounts for 1% of the total mass of the composition A.

[0074] Example 7

[0075] The difference between the solvent-free polyurethane stock solution and Example 1 is that the epoxy resin E44 accounts for 8% of the total mass of the composition A.

[0076] Example 8

[0077] The difference between the solvent-free polyurethane stock solution and Example 2 is that the original bisphenol A-modified polyoxyethylene-oxypropylene ether polyol of composition A and composition B is replaced by bisphenol A-modified polyether polyol with a bisphenol A mass content of about 18%.

[0078] Example 9

[0079] The difference between the solvent-free polyurethane stock solution and Example 2 is that the original bisphenol A-modified polyethylene oxide-propylene oxide ether polyol of composition A and composition B is replaced by bisphenol A-modified polyether polyol with a bisphenol A mass content of about 80%.

[0080] Example 10

[0081] The difference between the solvent-free polyurethane stock solution and Example 2 is that the original bisphenol A-modified polyethylene oxide-propylene oxide ether polyol of composition A and composition B is replaced by bisphenol A-modified polyether polyol with a number average molecular weight of 280.

[0082] Embodiment 11

[0083] The difference between the solvent-free polyurethane stock solution and Example 2 is that the original bisphenol A-modified polyethylene oxide-propylene oxide ether polyol of composition A and composition B is replaced by bisphenol A-modified polyether polyol with a number average molecular weight of 2000.

[0084] Example 12

[0085] The difference between the solvent-free polyurethane stock solution and Example 4 is that an equal amount of polyethylene adipate polyol with a number average molecular weight of 2000 is used to replace the polytetramethylene ether polyol and polyoxyethylene-oxypropylene ether polyol of composition A and composition B.

[0086] Comparative Example 1

[0087] The difference between the solvent-free polyurethane stock solution and Example 1 is that component A does not contain bisphenol A-modified polyethylene oxide-propylene oxide ether polyol.

[0088] Comparative Example 2

[0089] The difference between the solvent-free polyurethane stock solution and Example 1 is that component B does not contain bisphenol A modified polyethylene oxide-propylene oxide ether polyol.

[0090] Comparative Example 3

[0091] The difference between the solvent-free polyurethane stock solution and Example 1 is that component A and component B do not contain bisphenol A modified polyethylene oxide-propylene oxide ether polyol.

[0092] Comparative Example 4

[0093] The difference between the solvent-free polyurethane stock solution and Example 1 is that component B does not contain polytetramethylene ether polyol, and an equimolar amount of bisphenol A-modified polyoxyethylene-oxypropylene ether polyol is used to replace the polytetramethylene ether polyol.

[0094] Comparative Example 5

[0095] The difference between the solvent-free polyurethane stock solution and Example 4 is that component A does not contain epoxy resin.

[0096] Comparative Example 6

[0097] The difference between the solvent-free polyurethane stock solution and Example 4 is that the epoxy resin in component A is added to component B.

[0098] Comparative Example 7

[0099] The difference between the solvent-free polyurethane stock solution and Example 4 is that an equimolar amount of diphenylmethane diisocyanate is used to replace ortho-hexamethylene diisocyanate.

[0100] Preparation of solvent-free polyurethane resin film: The solvent-free polyurethane stock solutions of the above examples and comparative examples were mixed in a molar ratio of 1:1 between the NCO-reactive groups in component A and the NCO groups in the component, and then coated to form a solvent-free polyurethane resin film with a thickness of about 0.40 mm.

[0101] Preparation of synthetic leather: coating a surface layer resin on a release paper, adding a foaming agent to the solvent-free polyurethane stock solution of the above-mentioned embodiment and comparative example, mixing in a molar ratio of 1:1 between the reactive groups to NCO in component A and the NCO groups in the component, uniformly coating the surface layer resin, and attaching a base fabric, separating the release paper on the surface layer resin after aging to obtain synthetic leather.

[0102] The above polyurethane resin film and synthetic leather were subjected to the following performance tests:

[0103] Yellowing resistance: The polyurethane resin film is subjected to QUV yellowing resistance test (using UVA bulb) at 50°C and irradiated with ultraviolet light for X hours. The color change of the sample before and after the test is compared and divided into 1-5 levels. The best level 5 represents basically no color change, and 1 represents obvious color change.

[0104] Heat resistance: synthetic leather is placed in an oven at 160°C for 4 hours, and the surface softening of the sample after the scratch test is graded from 1 to 5. The best grade 5 means no scratches on the sample surface, grade 4 means slight scratches on the sample surface, grade 4 means slight changes in the surface texture, grade 3 means obvious changes in the surface texture, and grades 1 and 2 mean that the sample surface softens and the texture changes are obvious;

[0105] Alcohol resistance: 10×10cm synthetic leather was soaked in an alcohol solution with a relative concentration of 75%, and placed at room temperature for 24 hours. The surface condition of the sample after alcohol resistance and the change in peel strength of the test sample were observed, and the test was divided into 1-5 levels. The best level 5 means that the peel strength of the sample before and after the test decreased by less than 30%, and the leather sample had no curling. Level 4 means that the peel strength of the sample before and after the test decreased by less than 50%, and the leather sample had a slight curling. Level 3 means that the peel strength of the sample before and after the test decreased by less than 50%, and the leather sample had obvious curling. Level 2 means that the peel strength of the sample before and after the test decreased by more than 80%, and the leather sample had obvious curling. Level 1 means that the sample after the test has direct delamination and the leather sample curls.

[0106] Adhesion performance: Peel strength test of synthetic leather was carried out according to GB / T 1040.3-2006 standard;

[0107] Feel: By touching the surface of synthetic leather, compare the feel of the samples, and divide them into 1-5 levels. The higher the level, the softer the feel and the closer it is to the texture of genuine leather. The best level 5 means that the sample feels very soft and is closest to the texture of genuine leather. Level 1 means that the feel is stiff and has no genuine leather texture.

[0108] The properties of the polyurethane resin films and synthetic leathers prepared in the examples and comparative examples are as follows:

[0109]

[0110]

[0111] *: Component B is unstable and prone to agglomeration.

Claims

1. A solvent-free polyurethane stock solution, characterized in that The stock solution includes the following components: Composition A containing bisphenol A modified polyether polyol and epoxy resin, Composition B containing a polyurethane prepolymer, in, The polyurethane prepolymer is obtained by reacting bisphenol A modified polyether polyol, polyether polyol and aliphatic polyisocyanate.

2. The solvent-free polyurethane stock solution according to claim 1, characterized in that: The composition A has an OH value of 65 to 205 mg KOH / g.

3. The solvent-free polyurethane stock solution according to claim 1, characterized in that: The composition B has an NCO content of 8 to 28% by mass.

4. The solvent-free polyurethane stock solution according to claim 1 or 2, characterized in that: The epoxy value of the epoxy resin is 0.3-0.5, and the epoxy resin accounts for 3-5% of the total mass of the composition A.

5. The solvent-free polyurethane stock solution according to claim 1 or 2, characterized in that: The composition A, wherein the mass content of bisphenol A in the bisphenol A modified polyether polyol is 23-75%, and the number average molecular weight is 300-1000.

6. The solvent-free polyurethane stock solution according to claim 1, characterized in that: The composition A further contains a chain extender and / or polyether polyol.

7. The solvent-free polyurethane stock solution according to claim 1, characterized in that: The aliphatic polyisocyanate includes one or more of isophorone diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate and isomers and / or derivatives and / or modified polymers thereof.

8. The solvent-free polyurethane stock solution according to claim 6, characterized in that: The polyether polyol is selected from one or more of polyethylene oxide polyol, propylene oxide polyol, ethylene oxide-propylene oxide polyol and polyoxytetramethylene oxide polyol, and has a number average molecular weight of 1000 to 6000.

9. The solvent-free polyurethane stock solution according to claim 6, characterized in that: The chain extender includes C2-C6 diols, and further includes one or more of ethylene glycol, diethylene glycol, propylene glycol, butanediol, pentanediol, neopentyl glycol, and hexanediol.

10. A high-bonding polyurethane resin for synthetic leather prepared by using the solvent-free polyurethane stock solution of claim 1, characterized in that The high-bonding polyurethane resin for synthetic leather is obtained by reacting composition A and composition B, wherein the molar ratio of the reactive groups to NCO in composition A to the NCO groups in composition B is 0.98-1.10:1.

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