Preparation method of acrylate foam reinforcing glue

Abstract

The invention belongs to the technical field of adhesives, and discloses a preparation method of acrylate foam reinforcing rubber, which comprises the following steps: carrying out addition reaction on hydrogen-containing silicone oil by using allylamine hydrochloride, and then carrying out amidation reaction with 4-hydroxyphthalic anhydride to obtain hydroxybenzoic acid grafted silicone oil. The acrylate foam reinforcing adhesive contains hydrophilic hydroxyl, carboxyl and other groups, has good dispersibility in a water-based system of the acrylate foam reinforcing adhesive, and has excellent compatibility with water-based acrylic resin. Meanwhile, a hydroxyl group is contained, and in an isocyanate curing agent system, the hydroxyl group can be cured with the hydroxyl group of hydroxyl acrylic resin to generate a cross-linking reaction, so that the 180-degree peel strength, the permanent adhesion, the tensile shear strength, the water resistance and the heat resistance are improved; the adhesive has good practical application in the aspects of pressure-sensitive adhesive, foam adhesive tape, baking varnish plate bonding, electronic and electrical products, mechanical parts and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesives, and in particular relates to a method for preparing an acrylic foam reinforced adhesive. Background Art

[0002] Foam tape is mainly composed of foam substrate, release paper, pressure-sensitive adhesive and other adhesives. It has good wettability, adhesion, sealing, compression deformation resistance and other properties. It is widely used in products such as electronic appliances, industrial instruments, automotive accessories, porcelain plate pasting, anti-slip and cushioning shockproof packaging. Among them, the adhesive component directly determines the bonding properties of the foam tape. The common adhesive for foam tape is acrylic resin. Modifying acrylic resin adhesive to improve its peel strength, adhesion, water resistance, heat resistance and other properties is a research hotspot.

[0003] Silicone oil is a polysiloxane polymer with strong water resistance, good high temperature resistance, excellent electrical insulation, and is widely used in adhesives, coatings, plastics, etc. Patent technology document CN105001813B discloses vinyl silicone oil, hydrogenated silicone oil, acrylic rubber, ethyl silicate, vinyl double head sealer, etc. as raw materials. The prepared silicone-modified acrylic pressure-sensitive adhesive has the advantages of good solvent resistance, low initial adhesion and peeling force. However, the acrylic pressure-sensitive adhesive does not show good peel strength, tensile shear strength and other properties. In addition, as a hydrophobic substance, silicone oil has poor dispersibility in water-based adhesives and poor compatibility with water-based acrylic resins. Adding it to water-based adhesives will affect the performance of the adhesive. Summary of the invention

[0004] (I) Technical problems to be solved: In view of the deficiencies in the prior art, the present invention provides a method for preparing an acrylic foam reinforcing adhesive having strong bonding properties, good water resistance and good heat resistance.

[0005] (II) Technical solution: A method for preparing acrylic foam reinforced adhesive:

[0006] Step A, adding allylamine grafted hydrogen-containing silicone oil and 4-hydroxyphthalic anhydride into a solvent, stirring to react, removing the solvent by reduced pressure distillation, washing with methanol, and drying to obtain hydroxybenzoic acid grafted silicone oil.

[0007] Step B: adding water-based hydroxy acrylic resin, hydroxybenzoic acid grafted silicone oil, and isocyanate curing agent into water, stirring and mixing, and obtaining acrylic foam reinforcing adhesive.

[0008] Preferably, the solvent is N,N-dimethylformamide, N,N-dimethylacetamide or toluene.

[0009] Preferably, in step A, the mass of 4-hydroxyphthalic anhydride is 3.5-9% of the mass of the allylamine grafted hydrogen-containing silicone oil.

[0010] Preferably, in step A, the reaction is carried out at 15-40° C. for 12-24 h.

[0011] Preferably, in step A, the mass of the hydroxybenzoic acid grafted silicone oil and the isocyanate curing agent are 5-25% and 1.2-3% of the mass of the water-based hydroxy acrylic resin, respectively.

[0012] Preferably, the preparation method of allylamine grafted hydrogen-containing silicone oil is: add hydrogen-containing silicone oil, allylamine hydrochloride and sodium hydroxide to toluene, stir, add catalyst in nitrogen atmosphere, stir reaction, distill under reduced pressure, wash with saturated sodium bicarbonate solution, dry to obtain allylamine grafted hydrogen-containing silicone oil.

[0013] Preferably, the mass of the allylamine hydrochloride is 2-5% of the mass of the hydrogen-containing silicone oil.

[0014] Preferably, the reaction is carried out at 90-100° C. for 6-10 h.

[0015] Preferably, the catalyst is chloroplatinic acid-isopropanol solution.

[0016] (III) Technical effect: The present invention utilizes allylamine hydrochloride to carry out addition reaction on hydrogen-containing silicone oil, and then carries out amidation reaction with 4-hydroxyphthalic anhydride to obtain hydroxybenzoic acid grafted silicone oil, thereby introducing active groups such as benzene ring, hydroxyl group, carboxyl group, etc. into the side chain of silicone oil.

[0017] The present invention uses water-based hydroxy acrylic resin and isocyanate curing agent as the curing system of water-based foam adhesive, and hydroxybenzoic acid grafted silicone oil is used as an additive. The side chain of hydroxybenzoic acid grafted silicone oil contains hydrophilic carboxyl, hydroxyl and amide bonds, which improves the hydrophilicity of silicone oil, has good dispersibility in the water-based system of acrylic ester foam reinforcing adhesive, has excellent compatibility with water-based acrylic resin, and is conducive to improving the bonding strength and other properties of the adhesive.

[0018] The hydroxybenzoic acid grafted silicone oil of the present invention contains a hydroxyl group. In an isocyanate curing agent system, the hydroxyl group thereof can undergo a cross-linking reaction with the hydroxyl group of the hydroxy acrylic resin, thereby grafting the silicone oil to the molecular chain of the acrylic resin, thereby enhancing the bonding strength between the two. At the same time, after the silicone oil and the acrylic resin are cross-linked and cured, the cohesive strength of the acrylic resin adhesive is improved, and the adhesive performance of the adhesive is enhanced, thereby improving the 180° peel strength, the holding force and the tensile shear strength, and having better bonding performance.

[0019] The hydroxybenzoic acid grafted silicone oil of the present invention is uniformly dispersed in the water-based adhesive system, and has a silicone oil molecular chain and a benzene ring structure that are hydrophobic and water-resistant. After curing, a hydrophobic network is formed in the adhesive, which increases the water contact angle of the adhesive cured film and is beneficial to improving its water resistance. In addition, the silicone oil has the characteristic of high temperature resistance, and the heat-resistant benzene ring group is introduced into the silicone oil side chain, which undergoes a cross-linking reaction with the acrylic resin, thereby increasing the initial thermal decomposition temperature of the adhesive and having better heat resistance. The acrylic ester foam reinforcing adhesive of the present invention has good practical applications in pressure-sensitive adhesives, foam tapes, baking varnish board bonding, electronic and electrical products, and mechanical parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the reaction formula for preparing hydroxybenzoic acid grafted silicone oil. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The hydrogen content of the hydrogen-containing silicone oil of the present invention is 1.56%, Jining Fangyu Chemical Co., Ltd.

[0023] Water-based hydroxyl acrylic resin brand BH-811, Dongguan Guangtong Chemical Products Co., Ltd.

[0024] Isocyanate curing agent model Wanhua HT600, Jinan Hongwang Chemical Co., Ltd.

[0025] Example 1

[0026] (1) Add 5 g of hydrogenated silicone oil, 0.1 g of allylamine hydrochloride, and 43 mg of sodium hydroxide to 10 mL of toluene, stir, and then add 0.1 mL of an isopropanol solution containing 22 μg of catalyst chloroplatinic acid in a nitrogen atmosphere. Stir and react at 90° C. for 6 h, evaporate under reduced pressure, wash with a saturated sodium bicarbonate solution, and dry to obtain allylamine-grafted hydrogenated silicone oil.

[0027] (2) Add 10 g of allylamine grafted hydrogen silicone oil and 0.35 g of 4-hydroxyphthalic anhydride to N,N-dimethylformamide solvent, stir and react at 15°C for 24 hours, remove the solvent by vacuum distillation, wash with methanol, and dry to obtain hydroxybenzoic acid grafted silicone oil.

[0028] (3) Add 100 g of water-based hydroxy acrylic resin, 5 g of hydroxybenzoic acid grafted silicone oil, and 1.2 g of isocyanate curing agent to 120 mL of water, and stir to mix to obtain an acrylic foam reinforcing adhesive.

[0029] Example 2

[0030] (1) Add 5 g of hydrogenated silicone oil, 0.18 g of allylamine hydrochloride, and 77 mg of sodium hydroxide to 10 mL of toluene, stir, and then add 0.2 mL of an isopropanol solution containing 40 μg of chloroplatinic acid as a catalyst in a nitrogen atmosphere. Stir and react at 100° C. for 6 h, evaporate under reduced pressure, wash with a saturated sodium bicarbonate solution, and dry to obtain allylamine-grafted hydrogenated silicone oil.

[0031] (2) Add 10 g of allylamine grafted hydrogen silicone oil and 0.62 g of 4-hydroxyphthalic anhydride to toluene solvent, stir and react at 40° C. for 12 h, remove the solvent by vacuum distillation, wash with methanol, and dry to obtain hydroxybenzoic acid grafted silicone oil.

[0032] (3) Add 100 g of water-based hydroxy acrylic resin, 5 g of hydroxybenzoic acid grafted silicone oil, and 1.2 g of isocyanate curing agent to 120 mL of water, and stir to mix to obtain an acrylic foam reinforcing adhesive.

[0033] Example 3

[0034] (1) Add 5 g of hydrogenated silicone oil, 0.25 g of allylamine hydrochloride, and 108 mg of sodium hydroxide to 10 mL of toluene, stir, and then add 0.3 mL of an isopropanol solution containing 60 μg of chloroplatinic acid as a catalyst in a nitrogen atmosphere. Stir and react at 90° C. for 10 h, evaporate under reduced pressure, wash with a saturated sodium bicarbonate solution, and dry to obtain allylamine-grafted hydrogenated silicone oil.

[0035] (2) Add 10 g of allylamine-grafted hydrogen-containing silicone oil and 0.9 g of 4-hydroxyphthalic anhydride to N,N-dimethylacetamide, stir and react at 40°C for 18 h, remove the solvent by vacuum distillation, wash with methanol, and dry to obtain hydroxybenzoic acid-grafted silicone oil.

[0036] (3) Add 100 g of water-based hydroxy acrylic resin, 5 g of hydroxybenzoic acid grafted silicone oil, and 1.2 g of isocyanate curing agent to 120 mL of water, and stir to mix to obtain an acrylic foam reinforcing adhesive.

[0037] Example 4

[0038] (1) Prepare hydroxybenzoic acid grafted silicone oil according to the method of Example 1.

[0039] (2) Add 100 g of water-based hydroxy acrylic resin, 10 g of hydroxybenzoic acid grafted silicone oil, and 1.6 g of isocyanate curing agent to 120 mL of water, and stir to mix to obtain an acrylic foam reinforcing adhesive.

[0040] Example 5

[0041] (1) Prepare hydroxybenzoic acid grafted silicone oil according to the method of Example 1.

[0042] (2) Add 100 g of water-based hydroxy acrylic resin, 15 g of hydroxybenzoic acid grafted silicone oil, and 2 g of isocyanate curing agent into 120 mL of water, stir and mix to obtain an acrylic foam reinforcing adhesive.

[0043] Example 6

[0044] (1) Prepare hydroxybenzoic acid grafted silicone oil according to the method of Example 1.

[0045] (2) Add 100 g of water-based hydroxy acrylic resin, 20 g of hydroxybenzoic acid grafted silicone oil, and 2.5 g of isocyanate curing agent to 120 mL of water, and stir to mix to obtain an acrylic foam reinforcing adhesive.

[0046] Example 7

[0047] (1) Prepare hydroxybenzoic acid grafted silicone oil according to the method of Example 1.

[0048] (2) Add 100 g of water-based hydroxy acrylic resin, 25 g of hydroxybenzoic acid grafted silicone oil, and 3 g of isocyanate curing agent into 120 mL of water, stir and mix to obtain an acrylic foam reinforcing adhesive.

[0049] Comparative Example 1

[0050] (1) Add 100 g of water-based hydroxy acrylic resin and 1.2 g of isocyanate curing agent to 120 mL of water, stir and mix to obtain an acrylic foam reinforcing adhesive.

[0051] Comparative Example 2

[0052] (1) Add 100 g of water-based hydroxyl acrylic resin, 5 g of hydrogenated silicone oil, and 1.2 g of isocyanate curing agent to 120 mL of water, and stir to mix to obtain an acrylic foam reinforcing adhesive.

[0053] Comparative Example 3

[0054] (1) Prepare allylamine-grafted hydrogen-containing silicone oil according to the method of Example 1.

[0055] (1) Add 100 g of water-based hydroxy acrylic resin, 5 g of allylamine-grafted hydrogenated silicone oil, and 1.2 g of isocyanate curing agent to 120 mL of water, and stir to mix to obtain an acrylic foam reinforcing adhesive.

[0056] The 180° peel strength of the acrylic foam reinforced adhesive was tested according to GB / T 2792-2014. The holding force was tested according to GB / T4851-2014. The tensile shear strength was tested according to GB / T 7124-2008. During the test, the curing temperature of the acrylic foam reinforced adhesive was 30°C and the curing time was 7 days.

[0057] Pour the acrylic foam reinforcing adhesive on the surface of the substrate and cure it at 30°C for 7 days. Then weigh 6 mg of the cured film and place it in a thermogravimetric analyzer to test the thermal properties in a nitrogen atmosphere at a temperature ranging from room temperature to 700°C.

[0058] The water contact angle of the cured film was tested according to the GB / T 30693-2014 method.

[0059] The test results are shown in Table 1.

[0060] Table 1 Acrylic foam reinforcement performance test

[0061]

[0062] Compared with Comparative Example 1, hydroxybenzoic acid grafted silicone oil is added to the acrylic foam reinforcing adhesive of Examples 1-7, and the 180° peel strength, holding force and tensile shear strength of the adhesive are significantly improved, and the initial thermal decomposition temperature is high, the water contact angle is large, and the heat resistance and water resistance are improved. This is attributed to the side chain of the hydroxybenzoic acid grafted silicone oil containing hydrophilic carboxyl, hydroxyl and amide bonds, which improves the hydrophilicity of the silicone oil, has good dispersibility in the aqueous system of the acrylic foam reinforcing adhesive, and has excellent compatibility with the aqueous acrylic resin. In addition, the hydroxybenzoic acid grafted silicone oil contains hydroxyl groups. In the isocyanate curing agent system, its hydroxyl group can undergo a cross-linking reaction with the hydroxyl group of the hydroxy acrylic resin, thereby grafting the silicone oil to the molecular chain of the acrylic resin, enhancing the bonding strength between the two. At the same time, after the silicone oil and the acrylic resin are cross-linked and cured, the cohesive strength of the acrylic resin adhesive is improved, and the adhesive performance of the adhesive is enhanced, thereby improving the 180° peel strength, holding force and tensile shear strength, and having better bonding performance.

[0063] Hydroxybenzoic acid grafted silicone oil is evenly dispersed in the water-based adhesive system. It has hydrophobic and water-resistant silicone oil molecular chains and benzene ring structures. After curing, it forms a hydrophobic network in the adhesive, which increases the water contact angle of the adhesive cured film and helps improve its water resistance. In addition, silicone oil has high temperature resistance. At the same time, the heat-resistant benzene ring group is introduced into the silicone oil side chain, which undergoes a cross-linking reaction with the acrylic resin, increasing the initial thermal decomposition temperature of the adhesive and having better heat resistance.

[0064] Compared with Example 1 and Comparative Example 1, Comparative Example 2 only adds hydrogen-containing silicone oil, which is hydrophobic, has poor water solubility and dispersibility in the aqueous system of acrylic foam reinforcing adhesive, does not contain hydroxyl groups, and cannot undergo cross-linking and curing reaction with acrylic resin, and does not significantly improve the 180° peel strength, holding force and tensile shear strength of the adhesive.

[0065] Compared with Example 1, Comparative Example 3 adds allylamine-grafted hydrogenated silicone oil, which does not contain hydrophilic carboxyl groups, hydroxyl groups and amide bonds, has poor water solubility and dispersibility in aqueous systems, and poor compatibility with aqueous acrylic resins, resulting in adhesive peel strength, tensile shear strength and other properties lower than those of Example 1. However, allylamine-grafted hydrogenated silicone oil contains amino groups, which can undergo curing and crosslinking reactions with isocyanate curing agents and hydroxy acrylic resins during the curing process, and the 180° peel strength, holding force and tensile shear strength and other properties are higher than those of Comparative Examples 1 and 2.

Claims

1. A method for preparing an acrylic foam reinforced adhesive, characterized in that: The preparation method comprises the following steps: Step A, adding allylamine grafted hydrogen-containing silicone oil and 4-hydroxyphthalic anhydride to a solvent, stirring to react, removing the solvent by distillation under reduced pressure, washing, and drying to obtain hydroxybenzoic acid grafted silicone oil; Step B: adding water-based hydroxy acrylic resin, hydroxybenzoic acid grafted silicone oil, and isocyanate curing agent into water, stirring and mixing, and obtaining acrylic foam reinforcing adhesive.

2. The method for preparing the acrylic foam reinforced adhesive according to claim 1, characterized in that: The solvent is N,N-dimethylformamide, N,N-dimethylacetamide or toluene.

3. The method for preparing the acrylic foam reinforced adhesive according to claim 1, characterized in that: In the step A, the mass of 4-hydroxyphthalic anhydride is 3.5-9% of the mass of the allylamine grafted hydrogen-containing silicone oil.

4. The method for preparing the acrylic foam reinforced adhesive according to claim 1, characterized in that: In the step A, the reaction is carried out at 15-40° C. for 12-24 h.

5. The method for preparing the acrylic foam reinforced adhesive according to claim 1, characterized in that: The mass of the hydroxybenzoic acid grafted silicone oil in step A is 5-25% of the mass of the water-based hydroxy acrylic resin.

6. The method for preparing the acrylic foam reinforced adhesive according to claim 1, characterized in that: The mass of the isocyanate curing agent in step A is 1.2-3% of the mass of the waterborne hydroxy acrylic resin.

7. The method for preparing the acrylic foam reinforced adhesive according to claim 1, characterized in that: The preparation method of the allylamine grafted hydrogen-containing silicone oil comprises the following steps: adding hydrogen-containing silicone oil, allylamine hydrochloride and sodium hydroxide into toluene, stirring, adding a catalyst in a nitrogen atmosphere, stirring for reaction, performing reduced pressure distillation, washing and drying to obtain the allylamine grafted hydrogen-containing silicone oil.

8. The method for preparing the acrylic foam reinforced adhesive according to claim 7, characterized in that: The mass of the allylamine hydrochloride is 2-5% of the mass of the hydrogen-containing silicone oil.

9. The method for preparing the acrylic foam reinforced adhesive according to claim 7, characterized in that: The reaction is carried out at 90-100°C for 6-10 h.

10. The method for preparing the acrylic foam reinforced adhesive according to claim 7, characterized in that: The catalyst is chloroplatinic acid-isopropanol solution.

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