One-component moisture-curing polyacrylate resin and preparation method thereof

Abstract

The invention belongs to the technical field of polymer materials, and particularly relates to a one-component moisture-curing polyacrylate resin and a preparation method thereof. The one-component moisture-curing polyacrylate resin comprises raw materials for preparation thereof, including: 87-97 parts by weight of a main monomer, 2-8 parts by weight of a functional monomer, 1-5 parts by weight of a silane compound, 0.1-0.5 parts by weight of a free radical initiator and 200-300 parts by weight of an organic solvent; wherein the main monomer is a (methyl) acrylate having an alkyl group containing 1-20 carbon atoms; the active group contained in the functional monomer is a carboxyl group or a hydroxyl group; and the active group contained in the silane compound is an epoxy group or an isocyanate group; the invention copolymerizes the acrylate monomer to obtain an acrylate resin having a higher monomer conversion rate, a higher molecular weight and a smaller molecular weight distribution, and then adds a silane monomer containing a specific active group at the end, and introduces a moisture-reactive silane functional group through a grafting reaction, and the operation is simple, the operation space is large, and the reaction is easy to control.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a single-component moisture-curing polyacrylate resin and a preparation method thereof. Background Art

[0002] Conventional polyacrylate resins are mainly two-component. Before use, the main glue and curing agent components need to be pre-mixed evenly. The problems with this two-component polyacrylate resin are: (1) the curing agent may have the problem of poor mixing; (2) after the curing agent is added, the glue has a limited storage time, that is, it has a certain open time and needs to be used up within a specified time, generally not more than 6 hours. Further storage may have the risk of gelling; (3) The pre-mixing operation itself also limits its application scenarios that require high-speed gluing.

[0003] One-component polyacrylate resin can solve the above problems of two-component resin. The curing methods of one-component polyacrylate resin can be heat curing, UV light curing, electron beam irradiation curing and moisture curing. One of the more special methods is the moisture curing method, which uses the trace amount of water molecules in the environment to penetrate into the polyacrylate molecular structure and react with the activatable groups in the structure to cure. In order to obtain a moisture-curable polyacrylate resin, Chinese invention patent CN114144442A introduces a synthesis scheme for preparing moisture-curable polyacrylate, which introduces moisture-reactive silyl functional groups into the side chains of acrylate polymers by free radical polymerization, and has the ability to cure by a condensation mechanism in the presence of moisture and a catalyst. However, in this scheme, since the reactivity ratio of silane-type (meth)acrylate and conventional acrylate may be greatly different, the silane-type (meth)acrylate monomer may have problems such as low conversion rate, tendency to self-polymerization and influence on the overall reaction rate during the reaction, resulting in problems such as relatively concentrated distribution of the silane-type (meth)acrylate monomer in the entire molecular chain, high monomer residue, small molecular weight and wide molecular weight distribution. Summary of the invention

[0004] The object of the present invention is to provide a one-component moisture-curable polyacrylate resin and a preparation method thereof.

[0005] In order to solve the above technical problems, the present invention provides a one-component moisture-curing polyacrylate resin, the preparation raw materials comprising: 87 to 97 parts by weight of a main monomer, 2 to 8 parts by weight of a functional monomer, 1 to 5 parts by weight of a silane compound, 0.1 to 0.5 parts by weight of a free radical initiator and 200 to 300 parts by weight of an organic solvent; wherein the main monomer is a (methyl)acrylate having an alkyl group containing 1 to 20 carbon atoms; the active group contained in the functional monomer is a carboxyl group or a hydroxyl group; and the active group contained in the silane compound is an epoxy group or an isocyanate group.

[0006] Further, the main monomer is one or more of methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate.

[0007] Furthermore, the main monomer is a (meth)acrylate having an alkyl group containing 1 to 12 carbon atoms.

[0008] Furthermore, the functional monomer is one or more of (meth)acrylic acid, hydroxyethyl (meth)acrylate, and hydroxypropyl (meth)acrylate.

[0009] Furthermore, the silane compound is one or more of γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, 3-(2,3-epoxypropyloxy)propylmethyldimethoxysilane, 3-(2,3-epoxypropyloxy)propylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltriethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, 3-isocyanatepropyltrimethoxysilane, and 3-isocyanatepropylmethyldimethoxysilane.

[0010] Furthermore, the free radical initiator is an azo or peroxide initiator.

[0011] Furthermore, the organic solvent is one or more of ethyl acetate, butyl acetate, butanone, methyl isobutyl ketone, toluene, and xylene.

[0012] On the other hand, the present invention also provides a method for preparing a one-component moisture-curing polyacrylate resin, comprising: mixing and stirring 87 to 97 parts by weight of a main monomer, 2 to 8 parts by weight of a functional monomer and 150 to 250 parts by weight of an organic solvent, heating to a first reaction temperature under nitrogen protection, and then adding 0.1 to 0.5 parts by weight of a free radical initiator for copolymerization to obtain an acrylate macromolecular main chain; adjusting the temperature to a second reaction temperature, adding 1 to 5 parts by weight of a silane compound for further reaction so as to graft it onto the acrylate macromolecular main chain; adding an appropriate amount of an organic solvent for dilution, and discharging the material after cooling to obtain a moisture-curing polyacrylate resin.

[0013] Furthermore, the first reaction temperature is 60 to 80°C.

[0014] Furthermore, the second reaction temperature is 40-60°C.

[0015] The beneficial effect of the present invention is that the present invention first copolymerizes acrylate monomers to obtain acrylate resins with higher monomer conversion rate, higher molecular weight and smaller molecular weight distribution, and then further adds silane monomers containing specific active groups at the ends, and introduces moisture-reactive silane functional groups through grafting reactions. The operation is simple, the operation space is large, and the reaction is easy to control. The single-component moisture-curing polyacrylate resin glue prepared in this way has high monomer conversion rate, low monomer residue and high resin cohesion.

[0016] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0017] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a flow chart for the preparation of one-component moisture-curing polyacrylate resin. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0021] "KH-560" in the examples is γ-glycidyloxypropyltrimethoxysilane with the product model KH-560; "KH-901" is 3-isocyanatepropyltrimethoxysilane with the product model KH-901; "KH-570" is γ-methacryloxypropyltrimethoxysilane with the product model KH-570.

[0022] (1) Wet curing time test method: Place the coated sample in a 50°C, 65% humidity environment, start sampling from the 5th hour, and then take samples every 1 hour to test the degree of crosslinking. The time when the degree of crosslinking reaches the maximum is the wet curing time of the sample.

[0023] (2) Cross-linking degree test method: Take an appropriate amount of sample, weigh the exact mass M1 on an analytical balance, put the sample into a container of appropriate size, add an appropriate amount of ethyl acetate to completely soak the sample, filter the sample after 24 hours, the mass of the filter is M2, put the filtered sample and the filter into 120°C for drying, take out and weigh M3, the cross-linking degree is expressed by gel fraction = (M3-M2) / M1*100%.

[0024] Example 1

[0025] The present embodiment provides a one-component moisture-curable polyacrylate resin, the preparation raw materials of which include: 87 to 97 parts by weight of a main monomer, 2 to 8 parts by weight of a functional monomer, 1 to 5 parts by weight of a silane compound, 0.1 to 0.5 parts by weight of a free radical initiator, and 200 to 300 parts by weight of an organic solvent; wherein the main monomer is a (methyl)acrylate having an alkyl group containing 1 to 20 carbon atoms; the active group contained in the functional monomer is a carboxyl group or a hydroxyl group; and the active group contained in the silane compound is an epoxy group or an isocyanate group.

[0026] In this embodiment, the single-component moisture-curable polyacrylate resin has the advantages of high monomer copolymerization activity, large molecular weight, and small molecular weight distribution.

[0027] In this embodiment, the main monomer is one or more of methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate.

[0028] Preferably, the main monomer is a (meth)acrylate having an alkyl group containing 1 to 12 carbon atoms.

[0029] In this embodiment, the functional monomer is one or more of (meth)acrylic acid, hydroxyethyl (meth)acrylate, and hydroxypropyl (meth)acrylate.

[0030] In this embodiment, the silane compound is one or more of γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, 3-(2,3-epoxypropyloxy)propylmethyldimethoxysilane, 3-(2,3-epoxypropyloxy)propylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltriethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane of the epoxy group, and 3-isocyanatepropyltriethoxysilane, 3-isocyanatepropyltrimethoxysilane, and 3-isocyanatepropylmethyldimethoxysilane of the isocyanate group.

[0031] In this embodiment, the free radical initiator is an azo or peroxide initiator, including but not limited to benzoyl peroxide, tert-butyl benzoyl peroxide, azobisisobutyronitrile, azobisisoheptanenitrile, etc.

[0032] In this embodiment, the organic solvent is one or more of ethyl acetate, butyl acetate, butanone, methyl isobutyl ketone, toluene, and xylene.

[0033] In this embodiment, the number of silane compounds grafted to the main chain of the macromolecule directly affects the speed of wet curing, and the number of functional monomers on the main chain of the macromolecule determines the number of graftable sites of the silane compound. Therefore, when a faster wet curing speed or a higher degree of curing is required, the amount of the functional monomer needs to be as much as possible to provide more graftable sites, and the amount of the silane compound should also be increased accordingly, and vice versa. However, when the amount of the functional monomer is too high, it is possible to make the polarity of the resin too high, resulting in excessive water absorption and reduced glue adhesion. Experiments have shown that the amount of the functional monomer should be less than 7 parts, and when the amount of the functional monomer is too little, the silane compound has too few graftable sites, which will result in a slow curing speed or even no curing. Experiments have shown that the amount of the functional monomer should be greater than 2 parts. When there are enough grafting sites on the main chain of the polymer, but the silane compound is excessive, on the one hand, it may lead to too high a degree of curing, and on the other hand, too much silane compound that does not participate in the grafting reaction remains in the glue, which may also cause the glue's adhesion to decrease. When the amount of silane compound is too small, it may also lead to too slow curing speed or even no curing. Experiments have shown that the amount of silane compound should be controlled at 1 to 5 parts.

[0034] Example 2

[0035] like Figure 1 As shown, based on the above-mentioned embodiment 1, this embodiment 2 further provides a preparation method of a one-component moisture-curing polyacrylate resin, comprising: mixing and stirring 87 to 97 parts by weight of a main monomer, 2 to 8 parts by weight of a functional monomer and 150 to 250 parts by weight of an organic solvent, heating to a first reaction temperature under nitrogen protection, adding 0.1 to 0.5 parts by weight of a free radical initiator for copolymerization to obtain an acrylate macromolecular main chain; adjusting the temperature to a second reaction temperature, adding 1 to 5 parts by weight of a silane compound for further reaction so as to graft it to the acrylate macromolecular main chain; adding an appropriate amount of an organic solvent for dilution, and discharging the material after cooling to obtain a moisture-curing polyacrylate resin.

[0036] In this embodiment, the first reaction temperature is 60-80°C.

[0037] In this embodiment, the second reaction temperature is 40-60°C.

[0038] In this embodiment, the acrylate monomer is first copolymerized to obtain an acrylate resin with a higher monomer conversion rate, a higher molecular weight and a smaller molecular weight distribution, and then a silane monomer containing a specific active group at the end is further added, and a moisture-reactive silyl functional group is introduced through a grafting reaction. It is even possible to add a silane monomer containing a specific active group at the end to change its heat-curing properties into moisture-curing properties through a grafting reaction on the basis of commercially available polyacrylate resins without changing the properties of the masterbatch itself. The operation is simple, the operation space is large, and the reaction is easy to control. The single-component moisture-curing polyacrylate resin glue prepared in this way has a high monomer conversion rate, low monomer residue, and high resin cohesion, and can be used in sealants, cushioning foams, coatings, adhesives and other industries.

[0039] Example 3

[0040] Add 18 parts of methyl methacrylate, 72 parts of n-butyl acrylate, 7 parts of hydroxyethyl acrylate, and 150 parts of ethyl acetate to the reaction bottle, introduce enough nitrogen to exclude air, heat to 70°C, add 0.3 parts of azobisisobutyronitrile, react at 70°C for 3h, add 0.4 parts of azobisisobutyronitrile, continue to react for 4h, lower the reaction temperature to 45°C, add 3 parts of KH-901, continue to react at 45°C for 6h, end the reaction, add 50 parts of ethyl acetate to dilute, cool and discharge to obtain moisture-curable polyacrylate resin glue, and test its molecular weight and molecular weight distribution by GPC (gel permeation chromatography). The resin glue is coated on the surface of the release film, and the solvent is removed in a 100°C oven for 3min. The thickness of the dry film after coating is 30μm, and the curing speed and crosslinking degree are tested under 50°C and 65% humidity environment.

[0041] Example 4

[0042] Add 18 parts of methyl methacrylate, 15 parts of isobornyl acrylate, 56 parts of 2-ethylhexyl acrylate, 6 parts of hydroxyethyl acrylate, and 200 parts of ethyl acetate to the reaction bottle, introduce enough nitrogen to exclude air, heat to 80°C, add 0.2 parts of benzoyl peroxide, react at 80°C for 2h, add 0.4 parts of benzoyl peroxide, continue to react for 4h, lower the reaction temperature to 45°C, add 5 parts of KH-901, continue to react at 45°C for 6h, end the reaction, add 50 parts of ethyl acetate to dilute, cool and discharge to obtain moisture-cured polyacrylate resin glue, and test its molecular weight and molecular weight distribution by GPC. The resin glue is coated on the surface of the release film, and the solvent is removed in a 100°C oven for 3min. The thickness of the dry film after coating is 30μm, and the curing speed and crosslinking degree are tested at 50°C and 65% humidity.

[0043] Example 5

[0044] Add 15 parts of isobornyl acrylate, 70 parts of n-butyl acrylate, 10 parts of lauryl acrylate, 3 parts of acrylic acid, and 250 parts of ethyl acetate to the reaction bottle, introduce sufficient nitrogen to exclude air, heat to 60°C, add 0.2 parts of azobisisobutyronitrile, react at 60°C for 3h, add 0.4 parts of azobisisobutyronitrile, continue to react for 4h, then add 2 parts of KH-560, continue to react at 60°C for 6h, end the reaction, add 50 parts of ethyl acetate to dilute, cool and discharge to obtain moisture-cured polyacrylate resin glue, and test its molecular weight and molecular weight distribution by GPC. The resin glue is coated on the surface of the release film, and the solvent is removed in a 100°C oven for 3min. The thickness of the dry film after coating is 30μm, and the curing speed and crosslinking degree are tested at 50°C and 65% humidity.

[0045] Comparative Example 1

[0046] Add 18 parts of methyl methacrylate, 72 parts of n-butyl acrylate, 5 parts of hydroxyethyl acrylate, 5 parts of KH-570, and 150 parts of ethyl acetate to the reaction bottle, introduce sufficient nitrogen to exclude air, heat to 70°C, add 0.3 parts of azobisisobutyronitrile, react at 70°C for 3 hours, add 0.4 parts of azobisisobutyronitrile, continue to react for 4 hours, and then end the reaction, add 50 parts of ethyl acetate to dilute, cool and discharge to obtain moisture-curable polyacrylate resin glue, and use GPC to test its molecular weight and molecular weight distribution. The resin glue is coated on the surface of the release film, and the solvent is removed in a 100°C oven for 3 minutes. The thickness of the dry film after coating is 30μm, and the curing speed and crosslinking degree are tested at 50°C and 65% humidity.

[0047] Example 6

[0048] In this Example 6, the moisture-curing polyacrylate resin glue prepared in Examples 3 to 5 and the moisture-curing polyacrylate resin glue prepared in Comparative Example 1 were tested respectively. The main preparation materials and properties are shown in Table 1.

[0049] Table 1 Main preparation materials and performance comparison of moisture-curing polyacrylate resin glue

[0050]

[0051] It can be seen from the data in Table 2 that Examples 3 to 5 and Comparative Example 1 have successfully achieved the goal of moisture curing and obtained adhesive films with a certain degree of crosslinking, wherein Examples 3 to 5 have larger molecular weights and smaller molecular weight distributions, while Comparative Example 1 has a smaller molecular weight and a larger molecular weight distribution. Considering that Comparative Example 1 uses KH-570 containing double bonds to copolymerize with conventional acrylate monomers, the methyl groups on the double bonds of KH-570 make its copolymerization activity relatively low, affecting the smooth progress of free radical polymerization, while Examples 3 to 5 use a scheme of first copolymerizing conventional monomers and then grafting monomers with moisture curing activity, and the monomers have better copolymerization activity, so the molecular weight is larger and the distribution is lower.

[0052] Stability and storage of moisture-curing glue: In order to make the reaction and storage of moisture-curing glue more stable, the reaction and dilution solvents need to be dehydrated, such as by distillation or adding a desiccant to reduce the water content of the solvent to below 300ppm. The reacted glue needs to be sealed and stored.

[0053] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for preparing a one-component moisture-curing polyacrylate resin, characterized in that: The raw materials include: 87-97 parts by weight of main monomer, 2-8 parts by weight of functional monomer, 1-5 parts by weight of silane compound, 0.1-0.5 parts by weight of free radical initiator and 200-300 parts by weight of organic solvent; wherein The main monomer is a (meth)acrylate having an alkyl group containing 1 to 20 carbon atoms; The active group contained in the functional monomer is a carboxyl group or a hydroxyl group; and The active group contained in the silane compound is an epoxy group; The silane compound is one or more of γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltriethoxysilane, 3-(2,3-epoxypropyloxy)propylmethyldimethoxysilane, 3-(2,3-epoxypropyloxy)propylmethyldiethoxysilane, β-(3,4-epoxycyclohexyl)-ethyltriethoxysilane, and β-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane; The preparation method comprises: 87-97 parts by weight of the main monomer, 2-8 parts by weight of the functional monomer and 150-250 parts by weight of the organic solvent are mixed and stirred, heated to a first reaction temperature under nitrogen protection, and 0.1-0.5 parts by weight of a free radical initiator are added for copolymerization to obtain an acrylate macromolecular main chain; The temperature is adjusted to a second reaction temperature, and 1 to 5 parts by weight of a silane compound is added for further reaction so as to graft the silane compound onto the main chain of the acrylic ester macromolecule; An appropriate amount of organic solvent is added for dilution, and the material is discharged after cooling to obtain a moisture-curing polyacrylate resin.

2. The method for preparing a one-component moisture-curable polyacrylate resin according to claim 1, characterized in that: The main monomer is one or more of methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, lauryl (meth)acrylate, and isobornyl (meth)acrylate.

3. The method for preparing a one-component moisture-curable polyacrylate resin according to claim 2, characterized in that: The functional monomer is one or more of (meth)acrylic acid, hydroxyethyl (meth)acrylate, and hydroxypropyl (meth)acrylate.

4. The method for preparing a one-component moisture-curable polyacrylate resin according to claim 1, characterized in that: The free radical initiator is an azo or peroxide type initiator.

5. The method for preparing a one-component moisture-curable polyacrylate resin according to claim 4, characterized in that: The organic solvent is one or more of ethyl acetate, butyl acetate, butanone, methyl isobutyl ketone, toluene and xylene.

6. The method for preparing a one-component moisture-curable polyacrylate resin according to claim 1, characterized in that: The first reaction temperature is 60-80°C.

7. The method for preparing a one-component moisture-curable polyacrylate resin according to claim 1, characterized in that: The second reaction temperature is 40-60°C.

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