A two-component composition, process for its preparation and use

Abstract

The present application relates to a kind of two-component composition and its preparation method and application, belong to wood sealing primer technical field.The two-component composition described in the present application, including component A and component B;Component A includes the epoxy resin (1a) containing aromatic ring structure and containing two or more epoxy groups and the silane (1b) containing one epoxy group;In component A, the weight of silane (1b) accounts for 18-60wt% of the total weight of epoxy resin (1a) and silane (1b);Component B includes the silane (1c) containing one amine group and the substituted phenol (1d) of specific structure;In component B, the weight of substituted phenol (1d) accounts for 0.3-10wt% of the total weight of silane (1c) and substituted phenol (1d).The two-component composition of the present application can realize double curing, crosslinking density is high, has the advantages of excellent surface effect, polishing, flexibility, sealing property and warm wood effect, simultaneously without solvent or only low solvent content, especially suitable for wood sealing primer.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wood sealer primer, in particular to a two-component composition and a preparation method and application thereof. BACKGROUND

[0002] With the emphasis on environmental protection in the coating industry, the use of coatings containing high volatile organic compounds (VOC) is also facing more and more restrictions. The VOC in the coating mainly comes from organic solvents, and when the coating is dried to form a film, the organic solvent volatilizes to produce substances harmful to the human body. Traditional solvent-based wood coatings contain a large amount of organic solvents, which are harmful to the environment and health, so the development of low-VOC environmentally friendly wood coatings is an inevitable trend.

[0003] The first primer directly coated on the wood substrate is the key to affect the quality of the wood coating film. However, after applying the traditional wood primer on the wood substrate, the lignin, cellulose and other vessels in the wood substrate are prone to bulging, causing tannin, oil and other substances in the wood substrate to penetrate into the coating film, resulting in yellowing and discoloration of the coating film after drying.

[0004] To solve the above problems, the existing technology mostly uses water-based wood single-component or two-component sealing primer containing acrylic emulsion / resin / dispersion to coat the surface of the wood substrate, such as the water-based primer for wood enamel sealing disclosed in patent CN104761992B, the water-based wood sealing primer disclosed in CN105295607B, the water-based wood sealing primer of CN105602377B, and the two-component water-based wood sealing primer used in the anti-bleeding red oak two-component water-based wood coating structure disclosed in CN109111835B. However, the crosslinking density of these water-based wood sealing primers is not high, resulting in that the sealing performance of these water-based wood sealing primers is significantly poorer than that of the solvent-based system, and the anti-bulging and anti-tannin effects are not good; in addition, the drying speed of these water-based wood sealing primers is also slow, and multiple coatings are often needed to achieve the effect of a single coating of the solvent-based system. Moreover, since the glass transition temperature of the water-based acrylic resin used in these water-based wood sealing primers is relatively high, more film-forming aids need to be added in the water-based wood sealing primer formula, and although the VOC content is reduced compared with the solvent-based system, there is still room for further reduction. SUMMARY

[0005] Therefore, the purpose of the present application is to overcome the defects or deficiencies of the prior art, and to provide a two-component composition and a preparation method and application thereof. The coating film prepared from the two-component composition has the advantages of excellent surface effect, polishing performance, flexibility, sealing performance and warm wood effect, and the two-component composition does not contain solvent or contains only a small amount of organic solvent, which can be widely used in wood sealing primer as a composition to improve the performance of wood coatings.

[0006] To achieve the above object, the present application adopts the following technical solutions:

[0007] The present application provides a two-component composition comprising component A and component B; wherein:

[0008] The component A comprises epoxy resin (1a) and silane (1b); the epoxy resin (1a) contains aromatic ring structure and contains two or more epoxy groups; the epoxy resin (1a) includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin; the silane (1b) is a silane containing one epoxy group; in the component A, the weight of the silane (1b) accounts for 18-60wt% of the total weight of the epoxy resin (1a) and the silane (1b);

[0009] The component B comprises silane (1c) and substituted phenol (1d); the silane (1c) is a silane containing one amino group; the substituted phenol (1d) includes at least one of the compounds of formula (1); in the component B, the weight of the substituted phenol (1d) accounts for 0.3-10wt% of the total weight of the silane (1c) and the substituted phenol (1d);

[0010]

[0011] R1, R2, R3, R4, R5, R6 in formula (1) are each independently C1-C4 alkyl.

[0012] The inventors of the present application found through repeated research that the epoxy resin (1a) in the component A contains aromatic ring structure, has higher glass transition temperature, and has faster physical drying speed, so that when the two-component compound is used as a wood sealer primer, the drying property of the wood sealer primer can be improved; and the epoxy resin (1a) contains two or more (including two) epoxy groups, which can react with the active N-H on the amine group in the silane (1c) in the component B to increase the crosslinking density. The silane (1b) in the component A contains one epoxy group which can react with the active N-H on the amine group in the silane (1c) in the component B, and has very low viscosity, so that the viscosity of the component A obtained after mixing the epoxy resin (1a) and the silane (1b) is low, facilitating construction. At the same time, the silane groups in the silane (1b) and the silane (1c) can hydrolyze and crosslink with air and moisture in the wood substrate, or crosslink with the hydroxyl groups rich on the surface of the wood substrate, forming a dense crosslinking network, which, together with the crosslinking and curing of the epoxy groups and the active N-H on the amine group, forms double curing to further increase the crosslinking density, thus having excellent sealing property. The two-component composition of the present application can be used without or with less organic solvent, thus having very low organic solvent content.

[0013] The inventors of the present application found that the weight of silane (1b) in the A component accounts for 18-60 wt% of the total weight of epoxy resin (1a) and silane (1b) to achieve the efficacy of the present application, if the proportion of silane (1b) is too low, the surface effect and polishing of the coating film are not good; if the proportion of silane (1b) is too high, the crosslinking density after the hydrolysis of silane (1b) is too high, which will cause the coating film to be not flexible.

[0014] The inventors of the present application also found that it is necessary to use silane (1c) containing one amino group to achieve the efficacy of the present application, if silane containing multiple amino groups is used, the polishing of the coating film is not good, which may be due to the surface curing of silane with multiple amino groups too fast, forming a skin to isolate the water vapor in the air, preventing further hydrolysis reaction of silane groups inside the coating film.

[0015] The inventors of the present application also surprisingly found that the substituted phenol (1d) in the B component has an irreplaceable effect on improving the polishing of the coating film, the weight of the substituted phenol (1d) in the B component accounts for 0.3-10 wt% of the total weight of silane (1c) and substituted phenol (1d) to achieve the efficacy of the present application, if the B component does not contain substituted phenol (1d) or the content of substituted phenol (1d) is too low, it will cause the polishing of the coating film to be not good; if the content of substituted phenol (1d) is too high, it is easy to cause the two-component reaction to be too fast, the use time is shortened; and using other common tertiary amine accelerators, or using tertiary amine and alkyl phenol together, cannot achieve the effect of substituted phenol (1d) on promoting the polishing of the coating film.

[0016] As a preferred scheme of the present application, considering the low cost and easy availability of materials, the epoxy resin (1a) is preferably bisphenol A epoxy resin or phenolic epoxy resin. If the viscosity of the epoxy resin (1a) is too high, it will be not good for construction operation, or too much organic solvent needs to be added, which will cause the VOC emission to increase; the preferred epoxy resin (1a) used in the present application is liquid bisphenol A epoxy resin or phenolic epoxy resin at room temperature, such as NPEL-128, NPEL-134, NPPN-631, etc. of Nanya.

[0017] As a preferred scheme of the present application, the silane (1b) includes at least one of compounds of formula (2) and compounds of formula (3);

[0018]

[0019] In formula (2), R7, R8, R9 are each independently methyl or ethyl, and the statistical average value of x is 2-9; in formula (3), R 10 , R 11 , R 12 are each independently methyl or ethyl, and the statistical average value of y is 2-9.

[0020] As a more preferred aspect of the present application, the silane (1b) is preferably 3-glycidyloxypropyltrimethoxysilane (CAS: 2530-83-8) and / or 3-glycidyloxypropyltriethoxysilane (CAS: 2602-34-8) in view of low cost and easy availability of the material.

[0021] As a preferred aspect of the present application, the silane (1c) comprises at least one of the compounds of formula (4);

[0022]

[0023] R in formula (4) 13 , R 14 , R 15 are each independently methyl or ethyl.

[0024] As a more preferred aspect of the present application, the silane (1c) is preferably 3- aminopropyltrimethoxysilane (CAS: 13822-56-5) and / or 3-aminopropyltriethoxysilane (CAS: 919-30-2) in view of low cost and easy availability of the material.

[0025] The two-component composition of the present application can be free of or contain less organic solvent. When the two-component composition of the present application is selected to contain organic solvent according to actual needs, the A component and / or the B component further comprises organic solvent. By adding organic solvent in the A component and / or the B component, the film-forming property of the two-component composition can be improved and the drying speed can be adjusted.

[0026] Further, the weight of the organic solvent in the A component and / or the B component is 0.01-30 wt% of the total weight of the two-component composition. If the amount of the organic solvent added is too much, the drying speed will be reduced, and the VOC content in the two-component composition system will be increased.

[0027] Further, the organic solvent is at least one of alcohol ether, alcohol, ether, ester, ketone cosolvent. Preferably, the organic solvent is alcohol ether solvent, for example, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, propylene glycol butyl ether, ethylene glycol butyl ether, etc.

[0028] Further, the ratio of the total weight of the epoxy resin (1a) and the silane (1b) in the A component to the weight of the silane (1c) in the B component is 1:1 to 4:1. Too high or too low ratio will cause too many epoxy groups or active N-H groups on the amine groups not to participate in crosslinking reaction, resulting in a decrease in crosslinking density, which affects the blocking effect of the two-component composition as a wood sealer.

[0029] The present application also provides the use of the two-component composition of any of the above in a wood (two-component) sealer primer.

[0030] The resulting two-component composition is directly applied to a wood substrate as a wood sealer primer by mixing the A component with the B component.

[0031] Further, the wood (two-component) sealer primer is a low-solvent content wood (two-component) sealer primer, with an organic solvent content < 20 wt%, preferably an organic solvent content < 10 wt%, and more preferably a solvent content < 5 wt%.

[0032] Compared with the prior art, the present application has the following beneficial effects:

[0033] The two-component composition of the present application can achieve dual curing, has high crosslinking density, and has the advantages of excellent surface effect, sanding property, flexibility, sealing property, and warm wood effect, and is particularly suitable for use in wood sealer primers. DETAILED DESCRIPTION

[0034] The present application is further described below in conjunction with examples. These examples are only used to illustrate the present application and are not used to limit the scope of the present application. The experimental methods in the following examples are not specified, and are generally carried out according to conventional conditions in the art or according to the conditions recommended by the manufacturers; the raw materials, reagents, etc. used are commercially available raw materials and reagents, unless otherwise specified. Any non-essential changes and substitutions made by those skilled in the art on the basis of the present application are within the scope of the present application.

[0035] Raw materials used in the following examples or comparative examples:

[0036] (1) Epoxy resin (1a):

[0037] NPEL-128: Nan Ya, bisphenol A type epoxy resin, epoxy equivalent weight 184-190.

[0038] NPEL-134: Nan Ya, bisphenol A type epoxy resin, epoxy equivalent weight 230-270.

[0039] NPES-901: Nan Ya, bisphenol A type epoxy resin, epoxy equivalent weight 450-500.

[0040] NPEF-170: Nan Ya, bisphenol F type epoxy resin, epoxy equivalent weight about 160-180.

[0041] NPPN-631: Nan Ya, phenol type novolac epoxy resin, epoxy equivalent weight about 168-178.

[0042] (2) Epoxy resin (2a):

[0043] XY518: Anhui Xinyuan, hydrogenated bisphenol A epoxy resin, epoxy equivalent weight about 208-233.

[0044] (3) Silane (1b):

[0045] GX-560: Anhui Sibao, 3-glycidyloxypropyltrimethoxysilane, CAS: 2530-83-8.

[0046] GX-561: Anhui Sibao, 3-glycidyloxypropyltriethoxysilane, CAS: 2602-34-8.

[0047] KBM-4803: Japan Shin-Etsu, 8-glycidyloxyoctyltrimethoxysilane, CAS: 1239602-38-0.

[0048] KBM-303: Japan Shin-Etsu, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, CAS: 3388-04-3.

[0049] (4) Silane (1c):

[0050] GX-550: Anhui Sibao, 3-aminopropyltriethoxysilane, CAS: 919-30-2.

[0051] GX-540: Anhui Sibao, 3-aminopropyltrimethoxysilane, CAS: 13822-56-5.

[0052] (5) Silane (2c):

[0053] GX-792: Anhui Sibao, N-(beta-aminoethyl)-gamma-aminopropyltrimethoxysilane, CAS: 1760-24-3.

[0054] (6) Organic solvent:

[0055] DPM: Dow Chemical, dipropylene glycol monomethyl ether, CAS: 34590-94-8.

[0056] (7) Substituted phenol (1d):

[0057] DMP-30: 2,4,6-tris(dimethylaminomethyl)phenol, CAS: 90-72-2.

[0058] 2,4,6-tris(di-n-butylaminomethyl)phenol: the structure is consistent with formula (1), and R1, R2, R3, R4, R5, R6 are all n-butyl; the synthesis method of 2,4,6-tris(di-n-butylaminomethyl)phenol is as follows:

[0059] In a four-necked flask equipped with a reflux condenser and a stirrer, 94.1 g of phenol (1 mol) and 700 g of ethanol were added and stirred until dissolved. 284 g of formaldehyde 37% aqueous solution (3.5 mol) and 452.3 g of di-n-butylamine (3.5 mol) were slowly added, and the pH of the system was adjusted to 3-5 by dropwise addition of concentrated hydrochloric acid. The reaction was heated to 60-70°C and stirred under reflux, and the progress of the reaction was monitored by thin layer chromatography (TLC) until the phenol was consumed. After the reaction was completed, it was cooled to room temperature, neutralized to neutral (pH = 7-8) with sodium hydroxide solution, extracted with dichloromethane, and the organic phases were combined and dried over anhydrous sodium sulfate. The volatile fraction was removed by distillation under reduced pressure to obtain the product as a yellow liquid, 2,4,6-tris(di-n-butylaminomethyl)phenol.

[0060] Examples 1-16

[0061] Examples 1-16 each provide a two-component composition comprising a component A and a component B.

[0062] In the two-component composition of each example, the composition of the substances in component A and component B, and the specific selection and mass of each substance, please refer to Table 1.

[0063] In the two-component composition of each example, the proportion of the weight of silane (1b) in component A to the total weight of epoxy resin (1a) and silane (1b), the proportion of the weight of substituted phenol (1d) in component B to the total weight of silane (1c) and substituted phenol (1d), the content of organic solvent in the two-component composition, and the proportion of the total weight of epoxy resin (1a) and silane (1b) in component A to the weight of silane (1c) in component B, please refer to Table 2.

[0064] Examples 1-16 also each provide a method for preparing a two-component mixture, comprising the following steps: mixing the substances in component A according to the formula under the condition of 25±2°C to obtain component A, mixing the substances in component B according to the formula to obtain component B, and mixing component A and component B to obtain the two-component composition.

[0065] Table 1 Formula of two-component composition

[0066]

[0067]

[0068] Table 2 Proportion of formula of two-component composition

[0069]

[0070]

[0071] Comparative Examples 1-9

[0072] Comparative Examples 1-9 each provide a two-component composition including a Component A and a Component B.

[0073] In the two-component compositions of each of the Comparative Examples, the material composition of the Component A and the Component B, and the specific selection and mass of each material are as shown in Table 1.

[0074] In the two-component compositions of each of the Comparative Examples, the proportion of the weight of the silane (1b) in the Component A to the total weight of the epoxy resin (1a) and the silane (1b), the proportion of the weight of the substituted phenol (1d) in the Component B to the total weight of the silane (1c) and the substituted phenol (1d), the content of the organic solvent in the two-component composition, and the proportion of the total weight of the epoxy resin (1a) and the silane (1b) in the Component A to the weight of the silane (1c) in the Component B are as shown in Table 2.

[0075] The preparation method of the two-component mixture of Comparative Examples 1-9 includes the following steps: mixing the materials of the Component A according to the formula to obtain the Component A, mixing the materials of the Component B according to the formula to obtain the Component B, and mixing the Component A and the Component B to obtain the two-component composition at 25±2°C.

[0076] Comparative Example 10

[0077] Comparative Example 10 provides a water-based single-component sealing primer. The material composition of the water-based single-component sealing primer of this Comparative Example, and the specific selection and mass of each material are as shown in Table 3.

[0078] The preparation method of the water-based single-component sealing primer of this Comparative Example includes the following steps: mixing the materials according to the formula to obtain the water-based single-component sealing primer at 25±2°C.

[0079] Table 3 Formula of the water-based single-component sealing primer of Comparative Example 10

[0080] Material Weight (parts) Type Supplier PA-4853 80 Acrylic emulsion Kowa 8817 0.3 Defoamer Matsunosei Dipropylene glycol monobutyl ether 3.0 Co-solvent Dow Chemical Dipropylene glycol monomethyl ether 2.5 Co-solvent Dow Chemical Water 9.73 - - OS-1400 0.4 Wetting agent Kowa Tego Glide 410 0.2 Leveling agent Evonik HS-2000 1 Sanding aid Dongguan Hanwei BYK LAPONITE S 482 0.1 Bentonite BYK TAFIGEL PUR 65 0.25 Thickener Mingling L-44 2.5 Tannin protection aid Halox, USA Rheolate 299 0.02 Rheology aid Hermes

[0081] Performance Test

[0082] The two-component mixtures of Examples 1-16 and Comparative Examples 1-9, and the water-based single-component sealing primer of Comparative Example 10 are each subjected to the following performance test.

[0083] Construction Method: The wooden substrate is polished using 240# sandpaper. The two-component compositions of Examples 1-16 and Comparative Examples 1-9 obtained by mixing the Component A and the Component B at 25±2°C are each directly sprayed as a sealing primer on the wooden substrate at 25±2°C. The water-based single-component sealing primer of Comparative Example 10 is directly sprayed on the wooden substrate at 25±2°C. After spraying is completed, the substrate is dried overnight at 25±2°C.

[0084] Surface effect test: after the coating film is completely dried, whether the surface effect of the coating film is transparent and smooth is observed by eyes, and scored 1-5, 5 (transparent and smooth) is the best.

[0085] Polishability test: after overnight drying, polish with 400# sandpaper, observe the powder and sandpaper sticking, and score 1-5, 5 (more powder, no sandpaper sticking) is the best.

[0086] Cold and hot cycle test: according to ASTM D1211 method, 50 degrees per hour, room temperature 0.5 hours, -20 degrees 1 hour, room temperature 0.5 hours for a cycle, 10 cycles. Observe whether the coating film cracks.

[0087] Blocking test: spray the wood board with the blocking primer, and after the primer is completely dried, polish with 400# sandpaper, spray with water-based white paint, and bake at 50°C overnight, and observe the blocking effect after 3 months at room temperature. Observe the discoloration, and score 1-5, 5 (no obvious discoloration) is the best.

[0088] Warm wood effect test: observe the warm wood effect of the coating film, and score 1-5, 5 (the closest to the natural warm color effect of the wood substrate) is the best.

[0089] The test results are shown in Table 4:

[0090] Table 4: Blocking primer performance test results

[0091]

[0092]

[0093] The performance test results of Table 4 show that the two-component composition of Examples 1-16 of the present application, as a wood blocking primer, sprayed on the surface of the wood substrate, forms a coating film with excellent surface effect, polishability, flexibility, blocking property, and warm wood effect.

[0094] In the two-component composition of Comparative Example 1, the weight of the substituted phenol (1d) in the B component accounts for too low a proportion of the total weight of the silane (1c) and the tertiary amine (1d); in the two-component composition of Comparative Example 2, the B component does not contain the substituted phenol (1d); the polishability of the coating film formed by spraying the two-component composition of Comparative Example 1 and the two-component composition of Comparative Example 2, respectively, as a wood blocking primer on the surface of the wood substrate, is not good.

[0095] The common tertiary amine accelerators (triethylamine, triethanolamine) were used in the B component of the two-component compositions of Comparative Examples 3 and 4; the tertiary amine (triethylamine) was used in combination with the alkyl phenol (dodecyl phenol) as accelerators in the B component of the two-component composition of Comparative Example 5; no substituted phenol (1d) was used in the B component of the two-component compositions of Comparative Examples 3-5, resulting in poor sandability of the coating film formed by spraying the two-component compositions of Comparative Examples 3-5 on the surface of the wood substrate as a wood sealer primer.

[0096] The proportion of the silane (1b) in the A component of the two-component composition of Comparative Example 6 was too high, resulting in poor flexibility of the coating film formed by spraying the two-component composition of Comparative Example 6 on the surface of the wood substrate as a wood sealer primer.

[0097] The proportion of the silane (1b) in the A component of the two-component composition of Comparative Example 7 was too low, resulting in poor surface effect and sandability of the coating film formed by spraying the two-component composition of Comparative Example 7 on the surface of the wood substrate as a wood sealer primer.

[0098] The aliphatic epoxy resin (2a) was used in the A component of the two-component composition of Comparative Example 8 instead of the aromatic epoxy resin (1a), resulting in poor sandability of the coating film formed by spraying the two-component composition of Comparative Example 8 on the surface of the wood substrate as a wood sealer primer.

[0099] The silane (1c) of formula (4) was not used in the B component of the two-component composition of Comparative Example 9, resulting in poor surface effect and sandability of the coating film formed by spraying the two-component composition of Comparative Example 9 on the surface of the wood substrate as a wood sealer primer.

[0100] The waterborne one-component sealer primer of Comparative Example 10 had poor sealing property and warm wood effect of the coating film formed by spraying it on the surface of the wood substrate.

[0101] The above-described examples only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, and the present application also intends to include these modifications and improvements.

Claims

1. A two-component composition, characterized in that: It contains component A and component B; wherein: Component A comprises: Epoxy resin (1a), wherein the epoxy resin (1a) contains an aromatic ring structure and contains two or more epoxy groups; the epoxy resin (1a) includes at least one of bisphenol A epoxy resin, bisphenol F epoxy resin, and phenolic epoxy resin. Silane (1b), wherein the silane (1b) is a silane containing an epoxy group; the silane (1b) is selected from at least one of the compounds of formula (2) and the compounds of formula (3); In equation (2), R7, R8, and R9 are each independently methyl or ethyl, and the statistical average of x is 2-9; in equation (3), R 10 R 11 R 12 Each can be independently methyl or ethyl, and the statistical average of y is 2-9; In component A, the weight of the silane (1b) accounts for 18-60 wt% of the total weight of the epoxy resin (1a) and the silane (1b); Component B comprises: Silane (1c), wherein the silane (1c) is a silane containing an amino group; the silane (1c) is selected from at least one of the compounds of formula (4); R in equation (4) 13 R 14 R 15 Each can be independently methyl or ethyl; Substituted phenol (1d), said substituted phenol (1d) includes at least one of the compounds of formula (1); In formula (1), R1, R2, R3, R4, R5, and R6 are each independently a C1-C4 alkyl group; In component B, the weight of the substituted phenol (1d) accounts for 0.3-10 wt% of the total weight of the silane (1c) and the substituted phenol (1d); The ratio of the total weight of the epoxy resin (1a) and the silane (1b) in component A to the weight of the silane (1c) in component B is 1:1 to 4:

1.

2. The two-component composition according to claim 1, characterized in that: The A component and / or the B component further contain an organic solvent, wherein the weight of the organic solvent is 0.01-30 wt% of the total weight of the two-component composition.

3. A method for preparing a two-component composition as described in any one of claims 1-2, characterized in that: Includes the following steps: The A component is obtained by mixing the B component.

4. The use of a two-component composition as described in any one of claims 1-2 in a wood sealing primer.

5. The application of the two-component composition according to claim 4 in wood sealing primer, characterized in that: The two-component composition is applied as a wood sealing primer to wood substrates.

6. The application of the two-component composition according to claim 4 or 5 in a wood sealing primer, characterized in that: The organic solvent content in the wood sealing primer is <20wt%.

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