阅读说明：本技术 一种丙烯酸改性聚硫醇固化剂及其制备方法 (Acrylic acid modified polythiol curing agent and preparation method thereof ) 是由 宋宁 伍世钰 陈韬 苏光临 宁汉焱 廖家欣 于 2021-02-01 设计创作，主要内容包括：本发明属于环氧树脂固化剂领域,特别是涉及一种丙烯酸改性聚硫醇固化剂及其制备方法,所述丙烯酸改性聚硫醇固化剂,其制备原料包括丙烯酸酯、多巯基多醇酯、促进剂、多环氧基醚类物质；所述丙烯酸酯和多巯基多醇酯的重量比为1：(4-6)。本发明提供的丙烯酸改性聚硫醇固化剂与环氧树脂E51反应,凝胶时间＜9min,表干时间为12-18min,在25℃的粘度3500-5000cp.s,维卡温度≥80℃,硬度≥93(邵氏B),拉伸强度≥38MPa；本发明提供的固化剂多项性能优于市面上现有的聚硫醇固化剂,具有较高的实用意义。(The invention belongs to the field of epoxy resin curing agents, and particularly relates to an acrylic acid modified polythiol curing agent and a preparation method thereof, wherein the preparation raw materials of the acrylic acid modified polythiol curing agent comprise acrylate, multi-thiol polyol ester, an accelerator and multi-epoxy ether substances; the weight ratio of the acrylic ester to the multi-mercapto polyol ester is 1: (4-6). The acrylic acid modified polythiol curing agent provided by the invention reacts with epoxy resin E51, the gel time is less than 9min, the surface drying time is 12-18min, the viscosity at 25 ℃ is 3500-5000cp.s, the Vicat temperature is more than or equal to 80 ℃, the hardness is more than or equal to 93 (Shore B), and the tensile strength is more than or equal to 38 MPa; the curing agent provided by the invention has multiple performances superior to the existing polythiol curing agent on the market, and has higher practical significance.)

1. An acrylic acid modified polythiol curing agent is characterized in that raw materials for preparing the curing agent comprise acrylate, multi-thiol polyol ester, an accelerant and multi-epoxy ether substances; the weight ratio of the acrylic ester to the multi-mercapto polyol ester is 1: (4-6).

2. The acrylic-modified polythiol curing agent of claim 1, wherein the acrylate contains non-polar cycloalkyl groups.

3. The acrylic-modified polythiol curing agent of claim 2, wherein the acrylate contains 1 to 6 non-polar cycloalkyl groups.

4. The acrylic-modified polythiol curing agent of any of claims 1-3, wherein the polythiol ester comprises from 2 to 6 thiol groups.

5. The acrylic-modified polythiol curing agent of claim 4, wherein the polyepoxy ether has an epoxy value of 0.5 to 0.75eq/100 g.

6. The acrylic-modified polythiol curing agent of claim 5, wherein the weight ratio of the polyepoxy ether-based material to the polythiol ester is from 1: (7-10).

7. The acrylic-modified polythiol curing agent of claim 5 or 6, wherein the accelerator is selected from one or more of triethylamine, 2, 4, 6-tris (dimethylaminomethyl) phenol, triphenylphosphine, tributylphosphine, tris (p-methylphenyl) phosphine, tris (nonylphenyl) phosphine, tetraphenylphosphine-tetraphenylborate, benzyldimethylamine, α -methylbenzyldimethylamine, 2-phenylimidazole, 2-phenyl-4-methylimidazole.

8. The acrylic-modified polythiol curing agent of claim 1, wherein the weight ratio of the accelerator to the polythiol ester is from 1: (15-30).

9. A method of preparing an acrylic-modified polythiol curing agent according to any of claims 1-8, comprising: mixing acrylate, multi-mercapto-polyol ester and accelerator, reacting at 60-80 deg.C for 10-20h, adding multi-epoxy-ether substance, and reacting at 30-50 deg.C for 3-10 h.

10. The method of claim 9, wherein the acrylic-modified polythiol curing agent is prepared by: mixing acrylate, multi-mercapto-polyol ester and promoter, reacting at 60-80 deg.C for 10-20h, dripping multi-epoxy ether substance at 0.1-0.5L/min, and reacting at 30-50 deg.C for 3-10 h.

Technical Field

The invention belongs to the field of epoxy resin curing agents, and particularly relates to an acrylic acid modified polythiol curing agent and a preparation method thereof.

Background

The epoxy resin adhesive has good physical and chemical properties, excellent bonding property to the surfaces of various interface materials, excellent processing manufacturability and stability to most solvents, so the epoxy resin adhesive is widely applied to various departments of national defense and national economy, and has wide application in impregnation, laminating materials, adhesives, coatings and the like. Common curing agents for epoxy resins mainly include thiols, amines, acid anhydrides, imidazoles, and the like. Polythiol curing agents are strictly speaking polythiols, which can be formed by reacting beta-mercaptopropionic acid with pentaerythritol to form polythiol esters. When tertiary amine exists in the polythiol curing agent, thiol groups firstly react with the tertiary amine to generate thiol ions, and the thiol ions react with epoxy groups to crosslink and cure the epoxy. Traditional epoxy curing agents, such as low molecular weight polyamide, require 24 hours at normal temperature to enable epoxy to be completely gelled, and a polythiol system is used for only 5 minutes, so that polythiol is widely applied to rapid repair glue and winter work. Compared with other amines, anhydrides and other curing agents, polythiol can be rapidly cured at low temperature, and the requirements of indoor and outdoor use in certain low-temperature regions can be met, so that the working efficiency is effectively improved, and the cost is reduced. However, the current commercial products of polythiol curing agents and epoxy resins have the defects of poor heat resistance, high brittleness, low bonding strength, poor bending strength, low impact strength and the like. With the continuous progress of the technology, the requirement of the adhesive is higher and higher, and the traditional mercaptan curing agent cannot meet the requirement of practical application.

Disclosure of Invention

In view of the problems in the prior art, the invention provides an acrylic modified polythiol curing agent, which is prepared from raw materials including acrylate, multi-thiol polyol ester, accelerant, multi-epoxy ether substances; the weight ratio of the acrylic ester to the multi-mercapto polyol ester is 1: (4-6).

In a preferred embodiment of the present invention, the acrylate contains a nonpolar cycloalkyl group.

In a preferred embodiment of the present invention, the acrylate contains 1 to 6 nonpolar cycloalkyl groups.

In a preferred embodiment of the present invention, the polythiol ester contains 2 to 6 mercapto groups.

In a preferred embodiment of the present invention, the epoxy value of the polyepoxy ether is 0.5 to 0.75eq/100 g.

As a preferred technical solution of the present invention, the weight ratio of the polyepoxy ether substance to the polymercaptopolyether ester is 1: (7-10).

In a preferred embodiment of the present invention, the accelerator is one or more selected from triethylamine, 2, 4, 6-tris (dimethylaminomethyl) phenol, triphenylphosphine, tributylphosphine, tris (p-methylphenyl) phosphine, tris (nonylphenyl) phosphine, tetraphenylphosphine tetraphenylborate, benzyldimethylamine, α -methylbenzyldimethylamine, 2-phenylimidazole, and 2-phenyl-4-methylimidazole.

As a preferred technical solution of the present invention, the weight ratio of the accelerator to the polymercaptopolyether ester is 1: (15-30).

The second aspect of the present invention provides a preparation method of the acrylic modified polythiol curing agent, which comprises: mixing acrylate, multi-mercapto-polyol ester and accelerator, reacting at 60-80 deg.C for 10-20h, adding multi-epoxy-ether substance, and reacting at 30-50 deg.C for 3-10 h.

As a preferred technical scheme of the invention, the preparation method of the acrylic acid modified polythiol curing agent comprises the following steps: mixing acrylate, multi-mercapto-polyol ester and promoter, reacting at 60-80 deg.C for 10-20h, dripping multi-epoxy ether substance at 0.1-0.5L/min, and reacting at 30-50 deg.C for 3-10 h.

Compared with the prior art, the invention has the following beneficial effects:

(1) the acrylic acid modified polythiol curing agent provided by the invention reacts with epoxy resin E51, the gel time is less than 9min, the surface drying time is 12-18min, the viscosity at 25 ℃ is 3500-5000cp.s, the Vicat temperature is more than or equal to 80 ℃, the hardness is more than or equal to 93 (Shore B), and the tensile strength is more than or equal to 38 MPa; the curing agent provided by the invention has multiple performances superior to the existing polythiol curing agent on the market, and has higher practical significance;

(2) triethylamine is used as an accelerator, the acrylate contains 1-6 nonpolar naphthenic groups, and the multi-mercapto-polyol ester contains 2-6 mercapto groups, so that the addition reaction can be realized without participation of a solvent when the acrylate and the multi-mercapto-polyol ester are subjected to Michael addition reaction, and the obtained acrylic modified polythiol has moderate viscosity and cannot hinder the reaction from going on due to the absence of the participation of the solvent; meanwhile, under the condition, the Michael addition reaction time of the acrylate and the multi-mercapto-polyol ester is short, and the production efficiency is improved;

(3) the acrylate containing 2 nonpolar naphthenic groups is adopted in the application, so that the internal stress of the polythiol is obviously reduced, the volume shrinkage of the coating is reduced, and the characteristic indexes of the polythiol, such as adhesive force, shrinkage, impact resistance, scratch resistance, heat resistance and the like, are obviously improved;

(4) the polyepoxy ether substance with the epoxy value of 0.6-0.75eq/100g is adopted, a plurality of epoxy groups are contained in a molecule and react with sulfydryl in a product intermediate under the promotion of triethylamine to form a chain-shaped or net-shaped structure, and the synthesized polythiol curing agent has very good mechanical properties such as bonding strength, bending strength, compressive strength, impact strength and the like.

Detailed Description

The present invention is illustrated by the following specific embodiments, but is not limited to the specific examples given below.

The invention provides an acrylic acid modified polythiol curing agent in a first aspect, and the raw materials for preparing the acrylic acid modified polythiol curing agent comprise acrylic ester, multi-thiol polyol ester, an accelerant and multi-epoxy ether substances.

In one embodiment, the acrylate contains a non-polar cyclic alkyl group.

Preferably, the acrylate contains 1 to 6 non-polar cycloalkyl groups; more preferably, the acrylate contains 2 non-polar cycloalkyl groups.

As the acrylate containing 1 to 6 nonpolar cyclic alkyl groups in the present application, isobornyl acrylate, isobornyl methacrylate, norbornyl methacrylate, poly (isobornyl methyl acrylate), 5-norbornene-2-acrylic acid, 2-adamantyl acrylate and the like can be exemplified.

Preferably, the acrylate is isobornyl methacrylate.

The acrylate containing 2 nonpolar naphthenic groups is adopted in the application, so that the internal stress of the polythiol is obviously reduced, the volume shrinkage of the coating is reduced, and the characteristic indexes of the polythiol, such as adhesive force, shrinkage, impact resistance, scratch resistance, heat resistance and the like, are obviously improved.

In one embodiment, the polymercaptopolyether ester contains from 2 to 6 mercapto groups.

Examples of the polymercaptopolyether ester having 2 to 6 mercapto groups in the present application include ethylene glycol dimercaptoacetate, pentaerythritol tetramercaptoacetate, and the like.

Preferably, the polymercaptopolyether ester contains 4 mercapto groups.

Preferably, the polymercaptopolyether is pentaerythritol tetrakis (3-mercaptopropionate).

Examples of the polyepoxy ether substance include polyethylene glycol diglycidyl ether, trimethylolpropane glycidyl ether, diglycidyl ether, pentaerythritol glycidyl ether, bisphenol F diglycidyl ether, bisphenol a diglycidyl ether, diethylene glycol diglycidyl ether, and the like.

In one embodiment, the polyepoxy ether has an epoxy value of 0.5 to 0.75eq/100 g.

Preferably, the epoxy value of the polyepoxy ether is 0.6 to 0.75eq/100 g.

Preferably, the polyepoxy ether is trimethylolpropane glycidyl ether.

The polyepoxy ether substance with the epoxy value of 0.6-0.75eq/100g is adopted, a plurality of epoxy groups are contained in a molecule and react with sulfydryl in a product intermediate under the promotion of triethylamine to form a chain-shaped or net-shaped structure, and the synthesized polythiol curing agent has very good mechanical properties such as bonding strength, bending strength, compressive strength, impact strength and the like.

In one embodiment, the promoter is selected from one or more of triethylamine, 2, 4, 6-tris (dimethylaminomethyl) phenol, triphenylphosphine, tributylphosphine, tris (p-methylphenyl) phosphine, tris (nonylphenyl) phosphine, tetraphenylphosphine tetraphenylborate, benzyldimethylamine, α -methylbenzyldimethylamine, 2-phenylimidazole, 2-phenyl-4-methylimidazole.

Preferably, the promoter is triethylamine.

According to the preparation method, triethylamine is used as an accelerator, meanwhile, the acrylate contains 1-6 nonpolar cycloalkyl groups, and the multi-mercapto polyol ester contains 2-6 mercapto groups, so that the addition reaction can be realized without participation of a solvent in the Michael addition reaction of the acrylate and the multi-mercapto polyol ester, and the obtained acrylic acid modified polythiol has moderate viscosity and cannot hinder the reaction from proceeding due to the participation of no solvent. Meanwhile, under the condition, the Michael addition reaction time of the acrylate and the multi-mercapto-polyol ester is short, and the production efficiency is improved.

In one embodiment, the weight ratio of acrylate to polythiopolyol ester is 1: (4-6).

Preferably, the weight ratio of the acrylate to the polymercaptopolyether ester is 1: (4.9-5.3).

In one embodiment, the weight ratio of the polyepoxy ether-based material to the polymercaptopolyether ester is 1: (7-10).

Preferably, the weight ratio of the polyepoxy ether substance to the polymercaptopolyether ester is 1: (8-9.25).

In one embodiment, the weight ratio of accelerator to polymercaptopolyether ester is from 1: (15-30).

Preferably, the weight ratio of the accelerator to the polymercaptopolyether ester is 1: (16-25).

The second aspect of the present invention provides a preparation method of the acrylic modified polythiol curing agent, which comprises: mixing acrylate, multi-mercapto-polyol ester and accelerator, reacting at 60-80 deg.C for 10-20h, adding multi-epoxy-ether substance, and reacting at 30-50 deg.C for 3-10 h.

In one embodiment, the method of preparing the acrylic-modified polythiol curing agent comprises: mixing acrylate, multi-mercapto-polyol ester and promoter, reacting at 60-80 deg.C for 10-20h, dripping multi-epoxy ether substance at 0.1-0.5L/min, and reacting at 30-50 deg.C for 3-10 h.

In a preferred embodiment, the method for preparing the acrylic-modified polythiol curing agent comprises: mixing acrylate, multi-mercapto-polyol ester and accelerator, reacting at 60-80 deg.C for 10-12h, dripping multi-epoxy ether substance at 40-50 deg.C at 0.3-0.5L/min, and continuing to react for 5-6h to obtain the final product.

In a more preferred embodiment, the method for preparing the acrylic-modified polythiol curing agent comprises: mixing acrylate, multi-mercapto-polyol ester and an accelerant, reacting for 12h at 80 ℃, dropwise adding multi-epoxy ether substances at 45 ℃ at 0.3L/min, and continuing to react for 6h after dropwise adding is finished to obtain the acrylic ester/multi-mercapto-polyol ester/epoxy resin composite material.

The third aspect of the invention provides a use method of the acrylic modified polythiol curing agent, which comprises the following steps: comprising reacting an acrylic modified polythiol curing agent with an epoxy resin in a weight ratio of 1: (1-1.5) mixing and curing.

The epoxy resin described herein is not particularly limited and may be conventionally selected by those skilled in the art.

Examples

Hereinafter, the present invention will be described in more detail by way of examples, but it should be understood that these examples are merely illustrative and not restrictive. The starting materials used in the examples which follow are all commercially available unless otherwise stated.

Example 1

The embodiment 1 of the invention provides an acrylic acid modified polythiol curing agent, and the preparation method comprises the following specific steps:

starting the reaction kettle, and sequentially adding 15 parts by weight of isoborneol methacrylate, 74 parts by weight of tetra (3-mercaptopropionic acid) pentaerythritol and 3 parts by weight of triethylamine into the reaction kettle. And opening a temperature control device to control the temperature of the reaction kettle to be 80 ℃, and heating and stirring for 10 hours. After the reaction was completed, the temperature was adjusted to 45 ℃ and 8 parts by weight of trimethylolpropane glycidyl ether was added dropwise to the reaction vessel at 0.3L/min. After the completion of the dropwise addition, stirring was continued for 5 hours to obtain a product.

The resulting acrylic-modified polythiol curing agent was mixed with epoxy resin E51 at a ratio of 1: 1.25 weight ratio, and obtaining the adhesive.

Example 2

Embodiment 2 of the invention provides an acrylic acid modified polythiol curing agent, and the preparation method specifically comprises the following steps:

starting the reaction kettle, and sequentially adding 15 parts by weight of isoborneol methacrylate, 80 parts by weight of tetra (3-mercaptopropionic acid) pentaerythritol and 5 parts by weight of DMP-30 into the reaction kettle. And opening a temperature control device to control the temperature of the reaction kettle to be 80 ℃, and heating and stirring for 12 hours. After the reaction, the temperature was adjusted to 45 ℃ and 10 parts by weight of trimethylolpropane glycidyl ether was added dropwise to the reaction vessel at 0.3L/min. After the completion of the dropwise addition, stirring was continued for 6 hours to obtain a product.

The resulting acrylic-modified polythiol curing agent was mixed with epoxy resin E51 at a ratio of 1:1 weight ratio, and obtaining the adhesive.

Example 3

Embodiment 3 of the invention provides an acrylic acid modified polythiol curing agent, which comprises the following specific preparation methods:

starting the reaction kettle, and sequentially adding 15 parts by weight of isoborneol methacrylate, 74 parts by weight of tetra (3-mercaptopropionic acid) pentaerythritol and 3 parts by weight of triethylamine into the reaction kettle. And opening a temperature control device to control the temperature of the reaction kettle to be 80 ℃, and heating and stirring for 10 hours to obtain a product.

The resulting acrylic-modified polythiol curing agent was mixed with epoxy resin E51 at a ratio of 1: 1.25 weight ratio, and obtaining the adhesive.

Comparison scheme column 4

Mixing a Gabriel 3800 curing agent with an epoxy resin E51 at a ratio of 1: 1.25 weight ratio, and obtaining the adhesive.

Comparative example 5

And mixing and curing the Japanese Dongli QE-340 curing agent and the epoxy resin E51 in a weight ratio of 1:1 to obtain the adhesive.

Performance evaluation

1. Appearance, refractive index, chroma, active hydrogen equivalent: the refractive index and active hydrogen equivalent of the acrylic modified polythiol curing agent obtained in example 1-2 were measured, and the appearance was recorded, respectively, and the results are shown in Table 1. Wherein the refractive index is measured with an Abbe refractometer; the active hydrogen equivalent is determined by nuclear magnetic resonance hydrogen spectroscopy.

2. Testing the performance of the adhesive: the performances of the adhesives obtained in examples 1 to 3 and comparative examples 4 to 5 were tested, and the gelation time was tested according to GB12007.7-89 standard; the surface dry time test method comprises the following steps: respectively mixing a curing agent with epoxy resin E51 according to each example, coating the mixture on a glass slide with the coating thickness of 0.5mm, touching the surface of the coating with a PET plastic sheet after the gel is cured, and counting by using a stopwatch from the stirring of the mixture until the PET does not have adhesive force and residue on the coating, wherein the coating is dry, the room temperature is 25 ℃ and the humidity is 65%; the Shore hardness is tested according to the GB 2411-80 standard; the adhesive strength was tested using ASTM D3528-1996 (2016); the Vicat temperature is tested by adopting the GBT1633-2000 standard; the tensile strength is tested by adopting the GBT1040-92 standard; the water resistance was tested using the GBT1993-12-01 standard; the three-point bending strength is tested by adopting the GB/T6569-86 standard. The results are shown in Table 2.

TABLE 1

	Example 1	Example 2
			Appearance of the product	Light yellow liquid	Colorless transparent liquid
Refractive index	1.510	1.500
			Active hydrogen equivalent (g/eq)	242	183

TABLE 2

The foregoing examples are merely illustrative and serve to explain some of the features of the method of the present invention. The appended claims are intended to claim as broad a scope as is contemplated, and the examples presented herein are merely illustrative of selected implementations in accordance with all possible combinations of examples. Accordingly, it is applicants' intention that the appended claims are not to be limited by the choice of examples illustrating features of the invention. Also, where numerical ranges are used in the claims, subranges therein are included, and variations in these ranges are also to be construed as possible being covered by the appended claims.