Thermosetting formaldehyde-free acrylic resin and preparation method and application thereof

Abstract

The present invention relates to the technical field of acrylic resin adhesives, and discloses a thermosetting formaldehyde-free acrylic resin and a preparation method and application thereof. The thermosetting formaldehyde-free acrylic resin comprises: a structural unit A and a structural unit B; wherein the structural unit A has a structure shown in formula (1), and the structural unit B has a structure shown in formula (2), and the thermosetting formaldehyde-free acrylic resin further comprises: a structural unit C or a structural unit D; wherein the structural unit C has a structure shown in formula (3), and the structural unit D has a structure shown in formula (4). The present invention also relates to a preparation method and application of a thermosetting formaldehyde-free acrylic resin. The thermosetting formaldehyde-free acrylic resin provided by the present invention is clear and transparent, has low viscosity, high solid content, a curing temperature of 135-150°C, and is completely cured in 2-3 minutes.

Description

Technical Field

[0001] The invention relates to the technical field of acrylic resin adhesives, and in particular to a thermosetting formaldehyde-free acrylic resin and a preparation method and application thereof. Background Art

[0002] Glass fiber fluffy felt is composed of high-strength continuous monofilament fibers, with an incremental structure, high capture rate, good flame retardant performance, good compression performance, high temperature resistance, corrosion resistance, and can maintain its appearance unchanged. Its filter fiber is conducive to storing paint mist and dust. Due to the above excellent properties of glass fiber fluffy felt, it is widely used in many fields such as automobiles, chemicals, medical treatment, food, refrigerators, and household range hoods.

[0003] However, currently, glass fiber fluffy felt mostly adopts formaldehyde-containing adhesives, such as urea-formaldehyde resin, phenol formaldehyde resin, and melamine formaldehyde resin, which causes serious pollution to the environment and great harm to people's health during the preparation process of glass fiber fluffy felt.

[0004] Woodworking board is made by splicing small pieces of wood, multi-layer board is made by laminating and gluing multiple layers of veneer, and density board is particle board laminated with particles, all of which require adhesives.

[0005] In addition, the curing process of the adhesive consumes a lot of energy, so there is an urgent need to develop a formaldehyde-free adhesive with low curing temperature and short curing time. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems existing in the prior art and to provide a thermosetting formaldehyde-free acrylic resin and a preparation method and application thereof.

[0007] In order to achieve the above object, the present invention provides a thermosetting formaldehyde-free acrylic resin in a first aspect, wherein the thermosetting formaldehyde-free acrylic resin comprises: a structural unit A and a structural unit B; wherein the structural unit A has a structure shown in formula (1), and the structural unit B has a structure shown in formula (2).

[0008]

[0009] wherein R1 and R2 are each independently selected from hydrogen and C1-C 10 At least one of a linear or branched alkyl group;

[0010] The thermosetting formaldehyde-free acrylic resin further comprises: a structural unit C or a structural unit D; wherein the structural unit C has a structure shown in formula (3), and the structural unit D has a structure shown in formula (4),

[0011]

[0012] Wherein R3 is selected from C1-C10 At least one of a straight chain or branched chain alkyl group.

[0013] The second aspect of the present invention provides a method for preparing the thermosetting formaldehyde-free acrylic resin according to the first aspect, the method comprising: in the presence of an initiator, a chain transfer agent, a stabilizer, a solvent and a coupling agent, polymerizing a monomer represented by formula (I), a monomer represented by formula (II) and a monomer represented by formula (III) or a monomer represented by formula (IV) to obtain the thermosetting formaldehyde-free acrylic resin;

[0014]

[0015] Wherein, the definitions of R1, R2 and R3 are as described in the first aspect.

[0016] The third aspect of the present invention provides a thermosetting formaldehyde-free acrylic resin obtained by the preparation method described in the second aspect.

[0017] The fourth aspect of the present invention provides the use of the thermosetting formaldehyde-free acrylic resin described in the first aspect or the third aspect as an adhesive in the preparation of glass fiber fluffy felt, wood board, multilayer board and density board.

[0018] Through the above technical solution, the beneficial technical effects achieved by the present invention are as follows:

[0019] (1) The thermosetting formaldehyde-free acrylic resin provided by the present invention is clear and transparent, has low viscosity, high solid content, a curing temperature of 135-150° C., and is completely cured in 2-3 minutes. It has a good spraying effect on glass fiber fluffy felt, does not turn yellow, does not regain moisture, and has good flame retardancy. It can replace formaldehyde-containing resins such as urea-formaldehyde resin, phenol formaldehyde resin, and melamine formaldehyde resin, thereby avoiding pollution to the environment and harm to people's health.

[0020] (2) The number average molecular weight of the thermosetting formaldehyde-free acrylic resin provided by the present invention is 1500-2500, the solid content is 50-55%, and the Brookfield viscosity (25° C.) is 500-800 mPa·s; DETAILED DESCRIPTION

[0021] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0022] The first aspect of the present invention provides a thermosetting formaldehyde-free acrylic resin, comprising: a structural unit A and a structural unit B; wherein the structural unit A has a structure shown in formula (1), and the structural unit B has a structure shown in formula (2).

[0023]

[0024] wherein R1 and R2 are each independently selected from hydrogen and C1-C 10 At least one of a linear or branched alkyl group;

[0025] The thermosetting formaldehyde-free acrylic resin further comprises: a structural unit C or a structural unit D; wherein the structural unit C has a structure shown in formula (3), and the structural unit D has a structure shown in formula (4),

[0026]

[0027] Wherein R3 is selected from C1-C 10 At least one of a straight chain or branched chain alkyl group.

[0028] In the present invention, the C1-C 10 Examples of straight-chain or branched alkyl groups include, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, 2-methylhexyl, 2-ethylhexyl, 1-methylheptyl, 2-methylheptyl, n-octyl, isooctyl, n-nonyl, isononyl and 3,5,5-trimethylhexyl.

[0029] In some embodiments of the present invention, the thermosetting formaldehyde-free acrylic resin further comprises a structural unit E; the structural unit E has a structure shown in formula (5),

[0030]

[0031] wherein R4 is selected from hydrogen and C1-C 10 At least one of a linear or branched alkyl group;

[0032] R5 is -OCH3 and / or -OCH2CH2OH.

[0033] In some embodiments of the present invention, R1, R2 and R4 are each independently selected from at least one of hydrogen and a C1-C6 straight chain or branched alkyl group, preferably selected from at least one of hydrogen and a C1-C4 straight chain or branched alkyl group, more preferably hydrogen and / or methyl.

[0034] In some embodiments of the present invention, R3 is selected from at least one of C1-C6 straight chain or branched alkyl groups, preferably selected from at least one of C1-C4 straight chain or branched alkyl groups, and further preferably selected from at least one of methyl, ethyl and propyl groups.

[0035] In some embodiments of the present invention, the structural unit represented by formula (1) may be a structural unit derived from alkyl-substituted or unsubstituted acrylic acid, such as acrylic acid and methacrylic acid; the structural unit represented by formula (2) may be a structural unit derived from alkyl-substituted or unsubstituted acrylamide, such as acrylamide and methacrylamide; the structural unit represented by formula (3) may be a structural unit derived from an alkyl acrylate, such as methyl acrylate, ethyl acrylate, and butyl acrylate; the structural unit represented by formula (4) may be a structural unit derived from acrylonitrile; the structural unit represented by formula (5) may be a structural unit derived from methyl methacrylate and hydroxyethyl acrylate.

[0036] In some embodiments of the present invention, the molar ratio of structural unit A to structural unit B is 10:1-10:5, preferably 10:2-10:3.

[0037] The above ratio can be measured by infrared spectroscopy and nuclear magnetic resonance methods, or determined based on the preparation and feeding relationship.

[0038] In some embodiments of the present invention, the number average molecular weight of the thermosetting formaldehyde-free acrylic resin is 1500-2500, preferably 1850-2350, and more preferably 2050-2350. In the present invention, the number average molecular weight is tested by gel permeation chromatography. When the number average molecular weight is within this specific range, the viscosity of the resin is controlled for easy spraying.

[0039] In some embodiments of the present invention, the Brookfield viscosity of the thermosetting formaldehyde-free acrylic resin at 25° C. is 500-800 mPa·s. In the present invention, the Brookfield viscosity of the thermosetting formaldehyde-free acrylic resin at 25° C. is tested using a NDJ-8S5S9S digital viscometer.

[0040] In some embodiments of the present invention, the solid content of the thermosetting formaldehyde-free acrylic resin is 50-55%, preferably 52-55%. When the solid content is within this range, the strength of the product produced is good. The test method can be: take 100 grams of resin in an open glass container, bake at 150°C for 2 hours, and weigh the solid content taken.

[0041] In some embodiments of the present invention, the curing temperature of the thermosetting formaldehyde-free acrylic resin is 135-150°C, preferably 135-140°C.

[0042] In some embodiments of the present invention, the curing time of the thermosetting formaldehyde-free acrylic resin is 2-3 minutes.

[0043] The second aspect of the present invention provides a method for preparing the thermosetting formaldehyde-free acrylic resin according to the first aspect, the method comprising: in the presence of an initiator, a chain transfer agent, a stabilizer, a solvent and a coupling agent, polymerizing a monomer represented by formula (I), a monomer represented by formula (II) and a monomer represented by formula (III) or a monomer represented by formula (IV) to obtain the thermosetting formaldehyde-free acrylic resin;

[0044]

[0045] Wherein, the definitions of R1, R2 and R3 are as described in the first aspect.

[0046] In some embodiments of the present invention, the monomers of the polymerization reaction further include a monomer represented by formula (V):

[0047]

[0048] Wherein, the definitions of R4 and R5 are as described in the first aspect.

[0049] In some embodiments, the monomer represented by formula (I) is an alkyl-substituted or unsubstituted acrylic acid, such as acrylic acid and methacrylic acid; the monomer represented by formula (II) is an alkyl-substituted or unsubstituted acrylamide, such as acrylamide and methacrylamide; the monomer represented by formula (III) is an alkyl acrylate, such as methyl acrylate, ethyl acrylate, and butyl acrylate; the monomer represented by formula (IV) is acrylonitrile; and the monomer represented by formula (V) is methyl methacrylate and hydroxyethyl acrylate.

[0050] In some embodiments of the present invention, the initiator is selected from at least one of ammonium persulfate and potassium persulfate.

[0051] In some embodiments of the present invention, the weight proportion of the initiator is 3-10 parts, for example, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts, and any value within the range of any two of the above values, preferably 6-6.5 parts.

[0052] In some embodiments of the present invention, the chain transfer agent is selected from at least one of isopropyl alcohol, sodium bisulfite and sodium sulfite.

[0053] In some embodiments of the present invention, the weight proportion of the chain transfer agent is 10-50 parts, for example, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, and any value within the range of any two of the above values.

[0054] In some embodiments of the present invention, the stabilizer is selected from at least one of diethylene glycol methyl ether and diethylene glycol ethyl ether.

[0055] In some embodiments of the present invention, the weight proportion of the stabilizer is 2-25 parts, for example, 2 parts, 5 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, and any value within the range of any two of the above values.

[0056] In some embodiments of the present invention, the coupling agent is a silane coupling agent, preferably at least one selected from γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropyloxy)propyltrimethoxysilane.

[0057] In some embodiments of the present invention, the weight proportion of the coupling agent is 0.5-3 parts, for example, 0.5 parts, 0.8 parts, 1 parts, 1.2 parts, 1.5 parts, 2 parts, 2.3 parts, 2.7 parts, 3 parts, and any value within the range of any two of the above values.

[0058] In some embodiments of the present invention, the solvent is water.

[0059] In some embodiments of the present invention, the weight fraction of the solvent is 100-200 parts, for example, 100 parts, 110 parts, 120 parts, 125 parts, 130 parts, 140 parts, 150 parts, 160 parts, 170 parts, 180 parts, 190 parts, 200 parts, and any value within the range composed of any two of the above values.

[0060] In some embodiments of the present invention, the weight proportion of the monomer represented by formula (I) is 40-80 parts, for example, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, and any value within the range of any two of the above values, preferably 55-70 parts.

[0061] In some embodiments of the present invention, the total weight fraction of the monomer represented by formula (II), the monomer represented by formula (III) or the monomer represented by formula (IV) and the optional monomer represented by formula (V) is 5-40 parts, for example, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, and any value within the range of any two of the above values, preferably 20-40 parts.

[0062] In some embodiments of the present invention, the conditions of the polymerization reaction include: reflux; the reaction temperature is 78-82°C, for example, 78°C, 79°C, 80°C, 81°C, 82°C, and any value within the range composed of any two of the above numerical values; the reaction time is 40-70min, for example, 40min, 45min, 50min, 55min, 60min, 65min, 70min, and any value within the range composed of any two of the above numerical values.

[0063] In some embodiments of the invention, the method comprises the following steps:

[0064] (1) performing a first mixing of a portion of the monomer represented by formula (I), a portion of the initiator, a chain transfer agent, a stabilizer, and a portion of the solvent to obtain a first mixture;

[0065] (2) mixing the remaining part of the monomer represented by formula (I) with the monomer represented by formula (II), the monomer represented by formula (III) or the monomer represented by formula (IV) and the optional monomer represented by formula (V) for a second time to obtain a second mixture; dissolving the remaining part of the initiator in the remaining part of the solvent for a third time to obtain a third mixture;

[0066] (3) heating the first mixture to a polymerization reaction temperature, adding the second mixture and the third mixture dropwise thereto, and performing a polymerization reaction under reflux after the addition is complete;

[0067] (4) adding a coupling agent to the polymerization product, stirring and cooling to obtain the thermosetting formaldehyde-free acrylic resin.

[0068] In some embodiments of the present invention, the mass ratio of the monomer represented by formula (I) described in step (1) to the monomer represented by formula (I) described in step (2) is 1:5-12, for example, 1:5, 1:6, 1:7, 1:7.8, 1:8.1, 1:8.2, 1:8.5, 1:9, 1:10, 1:11, 1:11.7, and any value within the range of any two of the above values, preferably 1:5-7.

[0069] In some embodiments of the present invention, the mass ratio of the initiator described in step (1) to the initiator described in step (2) is 1:5-12, for example, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:8, 1:8.6, 1:9.2, 1:9.5, 1:10, 1:11, 1:12, and any value within the range of any two of the above values, preferably 1:5.5-9.5.

[0070] In some embodiments of the present invention, the mass ratio of the solvent described in step (1) to the solvent described in step (2) is 30:70.

[0071] In some embodiments of the present invention, the dropping time in step (3) is 2-3 hours.

[0072] In some embodiments of the present invention, after adding the coupling agent in step (4), the mixture is stirred and cooled to 40°C.

[0073] The third aspect of the present invention provides a thermosetting formaldehyde-free acrylic resin obtained by the preparation method described in the second aspect.

[0074] The fourth aspect of the present invention provides the use of the thermosetting formaldehyde-free acrylic resin described in the first aspect or the third aspect as an adhesive in the preparation of glass fiber fluffy felt, wood board, multilayer board and density board.

[0075] The present invention will be described in detail below through examples.

[0076] In the following examples and comparative examples, if no specific conditions are specified, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used, if no manufacturer is specified, are all conventional products that can be obtained through commercial channels.

[0077] Example 1

[0078] This example is used to illustrate the preparation of thermosetting formaldehyde-free acrylic resin.

[0079] (1) adding 18 kg of acrylic acid, 50 kg of isopropyl alcohol, 0.63 kg of ammonium persulfate, 25 kg of diethylene glycol methyl ether and 120 kg of water into a reaction kettle, stirring to obtain a first mixture and raising the temperature of the mixture to 82° C.;

[0080] (2) 152 kg of acrylic acid, 10 kg of methacrylamide and 5 kg of butyl acrylate were stirred uniformly to obtain a second mixture; 6 kg of ammonium persulfate was dissolved in 65 kg of water to obtain a third mixture;

[0081] (3) The second mixture and the third mixture are mixed and added dropwise to the first mixture in the reactor at a temperature of 82° C. The reflux reaction is maintained for 2 hours. After the addition is completed, the reaction is carried out for 40 minutes. Then, 2 kg of γ-aminopropyltriethoxysilane is added, stirred, and cooled to 40° C. to obtain a thermosetting formaldehyde-free acrylic resin.

[0082] Example 2

[0083] This example is used to illustrate the preparation of thermosetting formaldehyde-free acrylic resin.

[0084] (1) adding 18 kg of acrylic acid, 50 kg of isopropyl alcohol, 0.63 kg of ammonium persulfate, 27 kg of diethylene glycol methyl ether and 120 kg of water into a reaction kettle, stirring to obtain a first mixture and raising the temperature of the mixture to 82° C.;

[0085] (2) 147 kg of acrylic acid, 5 kg of acrylamide and 10 kg of ethyl acrylate were mixed uniformly to obtain a second mixture; 6 kg of ammonium persulfate was dissolved in 63 kg of water to obtain a third mixture;

[0086] (3) The second mixture and the third mixture are mixed and added dropwise to the first mixture in the reactor at a temperature of 82° C. The reflux reaction is maintained for 3 hours. After the addition is completed, the reaction is carried out for 70 minutes. Then, 2 kg of γ-aminopropyltriethoxysilane is added, stirred, and cooled to 40° C. to obtain a thermosetting formaldehyde-free acrylic resin.

[0087] Example 3

[0088] This example is used to illustrate the preparation of thermosetting formaldehyde-free acrylic resin.

[0089] (1) adding 15 kg of acrylic acid, 50 kg of isopropyl alcohol, 0.65 kg of ammonium persulfate, 10 kg of diethylene glycol methyl ether, 15 kg of diethylene glycol ethyl ether and 120 kg of water into a reaction kettle, stirring to obtain a first mixture and raising the temperature of the mixture to 82° C.;

[0090] (2) 150 kg of acrylic acid, 10 kg of acrylamide and 5 kg of acrylonitrile were mixed uniformly to obtain a second mixture; 6 kg of ammonium persulfate was dissolved in 65 kg of water to obtain a third mixture;

[0091] (3) The second mixture and the third mixture are mixed and added dropwise to the first mixture in the reactor at a temperature of 82°C. The reflux reaction is maintained for 2 hours. After the addition is completed, the reaction is continued for 50 minutes. Then, 2 kg of γ-(2,3-epoxypropoxy)propyltrimethoxysilane is added, stirred, and cooled to 40°C to obtain a thermosetting formaldehyde-free acrylic resin.

[0092] Example 4

[0093] This example is used to illustrate the preparation of thermosetting formaldehyde-free acrylic resin.

[0094] (1) adding 18 kg of acrylic acid, 52 kg of isopropyl alcohol, 1 kg of ammonium persulfate, 25 kg of diethylene glycol methyl ether and 120 kg of water into a reaction kettle, stirring to obtain a first mixture and raising the temperature of the mixture to 78° C.;

[0095] (2) 149 kg of acrylic acid, 5 kg of methacrylamide, 5 kg of butyl acrylate and 3 kg of hydroxyethyl acrylate were mixed uniformly to obtain a second mixture; 7 kg of ammonium persulfate was dissolved in 65 kg of water to obtain a third mixture;

[0096] (3) The second mixture and the third mixture are mixed and added dropwise to the first mixture in the reactor at a temperature of 78°C. The reflux reaction is maintained for 2.5 hours. After the addition is completed, the reaction is carried out for 60 minutes. Then, 2 kg of γ-aminopropyltriethoxysilane is added, stirred, and cooled to 40°C to obtain a thermosetting formaldehyde-free acrylic resin.

[0097] Example 5

[0098] This example is used to illustrate the preparation of thermosetting formaldehyde-free acrylic resin.

[0099] (1) adding 13 kg of acrylic acid, 5 kg of methacrylic acid, 50 kg of isopropyl alcohol, 0.7 kg of potassium persulfate, 25 kg of diethylene glycol methyl ether and 120 kg of water into a reaction kettle, stirring to obtain a first mixture and raising the temperature of the mixture to 82° C.;

[0100] (2) 145 kg of acrylic acid, 7 kg of methacrylic acid, 5 kg of methyl acrylate and 5 kg of methacrylamide were mixed uniformly to obtain a second mixture; 6 kg of potassium persulfate was dissolved in 65 kg of water to obtain a third mixture;

[0101] (3) The second mixture and the third mixture are mixed and added dropwise to the first mixture in the reactor at a temperature of 82°C. The reflux reaction is maintained for 3 hours. After the addition is completed, the reaction is carried out for 60 minutes. Then, 2 kg of γ-(2,3-epoxypropoxy)propyltrimethoxysilane is added, stirred, and cooled to 40°C to obtain a thermosetting formaldehyde-free acrylic resin.

[0102] Example 6

[0103] This example is used to illustrate the preparation of thermosetting formaldehyde-free acrylic resin.

[0104] (1) adding 18 kg of acrylic acid, 1 kg of potassium persulfate, 50 kg of isopropyl alcohol, 20 kg of diethylene glycol methyl ether, 5 kg of diethylene glycol ethyl ether and 120 kg of water into a reaction kettle, stirring to obtain a first mixture and raising the temperature of the mixture to 82° C.;

[0105] (2) 145 kg of acrylic acid, 5 kg of methyl acrylate, 7 kg of butyl acrylate and 5 kg of acrylamide were uniformly mixed to obtain a second mixture; 6.5 kg of potassium persulfate was dissolved in 65 kg of water to obtain a third mixture;

[0106] (3) The second mixture and the third mixture are mixed and added dropwise to the first mixture in the reactor at a temperature of 82°C. The reflux reaction is maintained for 2.5 hours. After the addition is completed, the reaction is carried out for 65 minutes. Then, 2 kg of γ-(2,3-epoxypropoxy)propyltrimethoxysilane is added, stirred, and cooled to 40°C to obtain a thermosetting formaldehyde-free acrylic resin.

[0107] Example 7

[0108] This example is used to illustrate the preparation of thermosetting formaldehyde-free acrylic resin.

[0109] (1) adding 18 kg of acrylic acid, 1 kg of ammonium persulfate, 50 kg of isopropyl alcohol, 10 kg of diethylene glycol methyl ether, 15 kg of diethylene glycol ethyl ether and 120 kg of water into a reaction kettle, stirring to obtain a first mixture and raising the temperature of the mixture to 82° C.;

[0110] (2) 140 kg of acrylic acid, 12 kg of methacrylamide, 5 kg of methyl methacrylate and 5 kg of butyl acrylate were mixed uniformly to obtain a second mixture; 6.5 kg of ammonium persulfate was dissolved in 70 kg of water to obtain a third mixture;

[0111] (3) The second mixture and the third mixture are mixed and added dropwise to the first mixture in the reactor at a temperature of 82°C. The reflux reaction is maintained for 2 hours. After the addition is completed, the reaction is carried out for 60 minutes. Then, 2 kg of γ-(2,3-epoxypropoxy)propyltrimethoxysilane is added, stirred, and cooled to 40°C to obtain a thermosetting formaldehyde-free acrylic resin.

[0112] Example 8

[0113] This example is used to illustrate the preparation of thermosetting formaldehyde-free acrylic resin.

[0114] (1) adding 18 kg of acrylic acid, 1 kg of ammonium persulfate, 50 kg of isopropyl alcohol, 25 kg of diethylene glycol methyl ether and 120 kg of water into a reaction kettle, stirring to obtain a first mixture and raising the temperature of the mixture to 82° C.;

[0115] (2) 142 kg of acrylic acid, 5 kg of methacrylamide, 5 kg of methyl acrylate, 5 kg of ethyl acrylate and 5 kg of butyl acrylate were mixed uniformly to obtain a second mixture; 5.5 kg of potassium persulfate was dissolved in 70 kg of water to obtain a third mixture;

[0116] (3) The second mixture and the third mixture are mixed and added dropwise to the first mixture in the reactor at a temperature of 82°C. The reflux reaction is maintained for 3 hours. After the addition is completed, the reaction is carried out for 60 minutes. Then, 2 kg of γ-(2,3-epoxypropoxy)propyltrimethoxysilane is added, stirred, and cooled to 40°C to obtain a thermosetting formaldehyde-free acrylic resin.

[0117] Comparative Example

[0118] Examples 1-8 disclosed in CN105713535 A were used as comparative examples.

[0119] Test Case

[0120] The thermosetting formaldehyde-free acrylic resins prepared in Examples 1-8 and Comparative Examples 1-8 were tested as follows:

[0121] Number average molecular weight: gel permeation chromatography;

[0122] Curing temperature: Take 1g of sample and measure the curing temperature of the sample at different temperatures of 120-180℃;

[0123] Curing time: The time required for the sample to cure at the curing temperature.

[0124] The results are shown in Table 1.

[0125] Table 1

[0126]

[0127]

[0128] It can be seen from the results in Table 1 that, compared with the previously disclosed resins, the curing temperature of the thermosetting formaldehyde-free acrylic resins prepared in Examples 1-8 of the present invention is reduced from 185-200°C to 135-150°C, and the curing time is reduced from 3-5min to 2-3min, which greatly reduces energy consumption.

[0129] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a thermosetting formaldehyde-free acrylic resin, characterized in that: The preparation method comprises: in the presence of an initiator, a chain transfer agent, a stabilizer, a solvent and a coupling agent, polymerizing a monomer represented by formula (I), a monomer represented by formula (II), a monomer represented by formula (III) and an optional monomer represented by formula (V) to obtain the thermosetting formaldehyde-free acrylic resin; ； wherein R1 and R2 are each independently selected from hydrogen and C1-C 10 At least one of a straight chain or branched chain alkyl group; R3 is selected from C1-C 10 At least one of a straight chain or branched chain alkyl group; R4 is selected from hydrogen and C1-C 10 At least one of the straight or branched alkyl groups; R5 is -OCH3 and / or -OCH2CH2OH; The weight proportion of the monomer represented by formula (I) is 170 parts, the weight proportion of the monomer represented by formula (II) is 10 parts, and the weight proportion of the monomer represented by formula (III) is 5 parts; Or, the weight parts of the monomer represented by formula (I) are 165 parts, the weight parts of the monomer represented by formula (II) are 5 parts, and the weight parts of the monomer represented by formula (III) are 10 parts; Or, the weight parts of the monomer represented by formula (I) are 167 parts, the weight parts of the monomer represented by formula (II) are 5 parts, the weight parts of the monomer represented by formula (III) are 5 parts; the weight parts of the monomer represented by formula (V) are 3 parts; Or, the weight parts of the monomer represented by formula (I) are 170 parts, the weight parts of the monomer represented by formula (II) are 5 parts, and the weight parts of the monomer represented by formula (III) are 5 parts; Or, the weight parts of the monomer represented by formula (I) are 163 parts, the weight parts of the monomer represented by formula (II) are 5 parts, and the weight parts of the monomer represented by formula (III) are 12 parts; Or, the weight parts of the monomer represented by formula (I) are 158 parts, the weight parts of the monomer represented by formula (II) are 12 parts, the weight parts of the monomer represented by formula (III) are 5 parts; the weight parts of the monomer represented by formula (V) are 5 parts; Or, the weight proportion of the monomer represented by formula (I) is 160 parts, the weight proportion of the monomer represented by formula (II) is 5 parts, and the weight proportion of the monomer represented by formula (III) is 15 parts.

2. The preparation method according to claim 1, wherein R1, R2 and R4 are each independently selected from at least one of hydrogen and a C1-C6 straight or branched alkyl group.

3. The preparation method according to claim 2, wherein R1, R2 and R4 are each independently selected from at least one of hydrogen and a C1-C4 straight or branched alkyl group.

4. The preparation method according to claim 3, wherein R1, R2 and R4 are hydrogen and / or methyl.

5. The preparation method according to claim 1, wherein R3 is at least one selected from C1-C6 straight chain or branched chain alkyl groups.

6. The preparation method according to claim 5, wherein: R3 is at least one selected from C1-C4 straight chain or branched chain alkyl groups.

7. The preparation method according to claim 6, wherein: R3 is at least one selected from the group consisting of methyl, ethyl and propyl.

8. The preparation method according to claim 1, wherein The initiator is selected from at least one of ammonium persulfate and potassium persulfate.

9. The preparation method according to claim 1, wherein The weight proportion of the initiator is 3-10 parts.

10. The preparation method according to claim 9, wherein: The weight proportion of the initiator is 6-6.5 parts.

11. The preparation method according to claim 1, wherein: The chain transfer agent is selected from at least one of isopropyl alcohol, sodium bisulfite and sodium sulfite.

12. The preparation method according to claim 1, wherein: The weight proportion of the chain transfer agent is 10-50 parts.

13. The preparation method according to claim 1, wherein The stabilizer is selected from at least one of diethylene glycol methyl ether and diethylene glycol ethyl ether.

14. The preparation method according to claim 1, wherein: The weight proportion of the stabilizer is 2-25 parts.

15. The preparation method according to claim 1, wherein: The coupling agent is a silane coupling agent.

16. The preparation method according to claim 15, wherein: The coupling agent is selected from at least one of γ-aminopropyltriethoxysilane and γ-(2,3-epoxypropyloxy)propyltrimethoxysilane.

17. The preparation method according to claim 1, wherein: The weight proportion of the coupling agent is 0.5-3 parts.

18. The preparation method according to claim 1, wherein: The solvent is water.

19. The preparation method according to claim 1, wherein: The weight proportion of the solvent is 100-200 parts.

20. The preparation method according to claim 1, wherein: The method comprises the following steps: (1) performing a first mixing of a portion of the monomer represented by formula (I), a portion of the initiator, a chain transfer agent, a stabilizer, and a portion of the solvent to obtain a first mixture; (2) mixing the remaining part of the monomer represented by formula (I) with the monomer represented by formula (II), the monomer represented by formula (III) and the optional monomer represented by formula (V) for a second time to obtain a second mixture; dissolving the remaining part of the initiator in the remaining part of the solvent for a third time to obtain a third mixture; (3) heating the first mixture to a polymerization reaction temperature, adding the second mixture and the third mixture dropwise thereto, and conducting a polymerization reaction under reflux conditions after the addition is complete; the reaction temperature is 78-82°C; the reaction time is 40-70 min; (4) adding a coupling agent to the polymerization reaction product, stirring and cooling to obtain the thermosetting formaldehyde-free acrylic resin; Wherein, the mass ratio of the monomer represented by formula (I) in step (1) to the monomer represented by formula (I) in step (2) is 1:5-12; The mass ratio of the initiator described in step (1) to the initiator described in step (2) is 1:5-12; The mass ratio of the solvent described in step (1) to the solvent described in step (2) is 30:

70.

21. The preparation method according to claim 20, wherein: The mass ratio of the monomer represented by formula (I) in step (1) to the monomer represented by formula (I) in step (2) is 1:5-7.

22. The preparation method according to claim 20, wherein: The mass ratio of the initiator described in step (1) to the initiator described in step (2) is 1:5.5-9.

5.

23. The preparation method according to claim 20, wherein: The dropping time in step (3) is 2-3 h.

24. The preparation method according to claim 20, wherein: Step (4) After adding the coupling agent, stir and cool to 40 °C.

25. Thermosetting formaldehyde-free acrylic resin obtained according to the preparation method described in any one of claims 1 to 24.

26. The thermosetting formaldehyde-free acrylic resin according to claim 25, wherein: The number average molecular weight of the thermosetting formaldehyde-free acrylic resin is 1500-2500.

27. The thermosetting formaldehyde-free acrylic resin according to claim 26, wherein: The number average molecular weight of the thermosetting formaldehyde-free acrylic resin is 1850-2350.

28. The thermosetting formaldehyde-free acrylic resin according to claim 27, wherein: The number average molecular weight of the thermosetting formaldehyde-free acrylic resin is 2050-2350.

29. The thermosetting formaldehyde-free acrylic resin according to claim 25, wherein: The Brookfield viscosity of the thermosetting formaldehyde-free acrylic resin at 25° C. is 500-800 mPa•s.

30. The thermosetting formaldehyde-free acrylic resin according to claim 25, wherein: The solid content of the thermosetting formaldehyde-free acrylic resin is 50-55%.

31. The thermosetting formaldehyde-free acrylic resin according to claim 30, wherein: The solid content of the thermosetting formaldehyde-free acrylic resin is 52-55%.

32. The thermosetting formaldehyde-free acrylic resin according to claim 25, wherein: The curing temperature of the thermosetting formaldehyde-free acrylic resin is 135-150°C.

33. The thermosetting formaldehyde-free acrylic resin according to claim 32, wherein: The curing temperature of the thermosetting formaldehyde-free acrylic resin is 135-140°C.

34. The thermosetting formaldehyde-free acrylic resin according to claim 25, wherein: The curing time of the thermosetting formaldehyde-free acrylic resin is 2-3 minutes.

35. Use of the thermosetting formaldehyde-free acrylic resin according to any one of claims 25 to 34 as an adhesive in the preparation of glass fiber fluffy mats, wood panels, multilayer boards and density boards.

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