JP2001011364A - Resin for coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an acrylic resin composition for a coating material improving its finished appearance and curing property, especially low temperature curing property without reducing its membrane physical properties and also having a low solution viscosity suitable for a high solidification. SOLUTION: This resin for a coating material is characterized by having 1-15 wt.% range content of a multi-vinyl monomer in its monomer composition, using a mercaptane containing hydroxyl or carboxyl group as a chain transfer agent in its polymerization and having <=20,000 weight-average molecular weight(Mw) of the produced polymer and also >=3 (Mw/Mn), the ratio of the weight average-molecular weight(Mw) to its number-average molecular weight (Mn).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a resin for a coating material having a low solution viscosity and suitable for high solidification.

[0002]

[Prior art and its problems] From the viewpoint of global environmental protection,
It is desired to reduce the amount of the organic solvent in the organic solvent type paint and to make it high solid. Conventionally, as a method of high solidification, a method of simply lowering the molecular weight of the resin to lower the viscosity is generally used.However, when the molecular weight of the resin is reduced, the curability is reduced or the physical properties of the coating film are reduced. And so on.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to improve the finish appearance, curability, especially low-temperature curability of a coating film without deteriorating the physical properties of the coating film, and moreover, it is suitable for high solidification. An object of the present invention is to provide an acrylic resin for paint having a low solution viscosity.

[0004]

Means for Solving the Problems The present inventors have intensively studied to solve the above-mentioned problems. as a result,
A resin having a specific molecular weight and a specific molecular weight distribution, which is obtained by polymerizing a polymerizable unsaturated monomer mixture containing a specific amount of a polyvinyl monomer using a specific chain transfer agent, solves all the above-mentioned problems. This led to the completion of the present invention.

That is, according to the present invention, as a radically polymerizable unsaturated monomer component constituting a polymer, when the content of the polyvinyl monomer in the total monomer component is within the range of 1 to 15% by weight, a chain is formed during polymerization. A mercaptan containing a hydroxyl group and / or a carboxyl group is used as a transfer agent, and the resulting polymer has a weight average molecular weight (Mw) of 5,000 to 20,
000 and a ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of 3 to 8 according to the present invention.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. A first purpose of the present invention is to lower the viscosity of a resin by branching the resin. Simply lowering the molecular weight of the resin to lower the viscosity will result in lowering of the curability and physical properties of the coating. Therefore, an important issue is how to reduce the resin viscosity at a certain molecular weight.
As one of the methods, it has been conventionally known that a resin having a branched structure lowers the viscosity. As a means for obtaining the branched structure, for example, a method of copolymerizing a macromonomer with another monomer, a method of modifying by grafting after polymerization, a method of using a polyfunctional initiator or a polyfunctional chain transfer agent, and the like are known. Have been.

In the present invention, the resin is positively branched by copolymerizing a polyvinyl monomer.

[0008] The use of a polyvinyl monomer is, theoretically, the introduction of one molecule of a polyvinyl monomer, the number of branches is increased by (n-1) x 2 with respect to n vinyl groups of the molecule. Very good branching efficiency. However, if the amount of the polyvinyl monomer exceeds a certain amount, gelling occurs, and therefore, in the present invention, the use of a chain transfer agent is essential for adjusting the molecular weight.

The second intention of the present invention is to pay attention to the fact that the chain transfer agent used for adjusting the molecular weight is introduced into the terminal of the resin, and by using a mercaptan containing a hydroxyl group and / or a carboxyl group, It is to actively introduce a cross-linking functional group into the terminal of the hyperbranched resin. The terminal functional group has a high degree of freedom and a very high reactivity. Due to this highly reactive functional group, the curability of the resin, particularly the curability at low temperatures, is improved, and the curability is ensured even when the molecular weight is reduced.

[0010] A third purpose of the present invention is that when a flexible polyvinyl monomer is used as the polyvinyl monomer, the connecting portion becomes flexible by introducing a flexible component, and the physical properties of the coating film can be maintained and improved. . FIG. 1 shows a schematic diagram of a molecular chain bonding model of a coating resin according to the present invention. In FIG. 1, X represents an OH group or a COOH group. The bonding between the molecular chains is based on a polyvinyl monomer (in FIG. 1, divinyl monomer). From this figure, it can be understood that the molecular chain is appropriately branched by the polyvinyl monomer, and an OH group or a COOH group having a large degree of freedom exists at the molecular terminal.

Details for exhibiting the above effects will be described.

The polyvinyl monomer has a molecular weight of 10
Those in the range of 0 to 1,000 are desirable. Molecular weight 1
If it is less than 00, it is too close to the main chain of the resin and does not branch effectively. Conversely, when the molecular weight exceeds 1,000, the number of moles of the polyvinyl monomer is reduced in the low molecular weight range intended by the present invention, and the degree of branching is undesirably reduced.

There is no particular limitation as long as it satisfies the above molecular weight range. Specific examples include the following, which can be used alone or in combination of two or more.

As the bifunctional polymerizable monomer, for example,
Divinylbenzene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate,
Propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6- Hexanediol di (meth) acrylate, bisphenol A ethylene oxide-modified di (meth) acrylate, di (meth) acrylate modified with bisphenol A and propylene oxide, 2-hydroxy-1-acryloxy-3-methacryloxypropane, tricyclo Decane dimethanol di (meth) acrylate, di (meth) acryloyloxyethyl acid phosphate; Kayarad HX-220, 620, R-604, MAND
A (above, products of Nippon Kayaku Co., Ltd.) and the like.

Examples of the polymerizable monomer having three or more functional groups include trimethylolpropane tri (meth) acrylate, trimethylolpropane and tri (meth) acrylate modified with ethylene oxide, trimethylolpropane and propylene oxide. Tri (meth) acrylate, glycerin tri (meth)
Tri (meth) acrylate modified with acrylate, glycerin and ethylene oxide, tri (meth) acrylate modified with glycerin and propylene oxide, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, isocyanuric acid and ethylene oxide Modified tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate and the like can be mentioned.

In addition, polyvinyl compounds other than those described above obtained by reacting a compound containing two or more functional groups with a vinyl compound having a group that reacts complementarily with the functional groups are naturally included.

The other polymerizable monomer copolymerizable with the polyvinyl monomer is not particularly limited as long as it is copolymerizable, and the functional group which can be used in combination is not particularly limited.
Specifically, the following are mentioned.

(1): Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, butyl n- (meth) acrylate, i- (meth) acrylate ) Butyl acrylate, t-
Butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth)
N-octyl acrylate, decyl (meth) acrylate,
Alkyl or cycloalkyl esters of acrylic acid or methacrylic acid having 1 to 30 carbon atoms, such as lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, and isobornyl (meth) acrylate; (2): methoxybutyl (meth) acrylate, (meth)
C2 to C2 of acrylic acid or methacrylic acid such as methoxyethyl acrylate, ethoxybutyl (meth) acrylate
18 alkoxyalkyl ester; acetoacetoxyethyl (meth) acrylate. (3): vinyl aromatic compounds such as styrene, α-methylstyrene, vinyltoluene, and p-chlorostyrene. (4): 2-hydroxyethyl (meth) acrylate,
A hydroxyalkyl ester having 2 to 8 carbon atoms of acrylic acid or methacrylic acid such as hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate. (5): an adduct of a hydroxyalkyl ester of acrylic acid or methacrylic acid and ε-caprolactone, for example, a monomer represented by Praxel FM-3 (“Placcel” is a trade name of Daicel Chemical Industries, Ltd.). (6): polyalkylene glycol mono (meth) acrylates, hydroxyalkyl vinyl ethers. (7): glycidyl (meth) acrylate, diglycidyl fumarate, allyl glycidyl ether, ε-caprolactone-modified glycidyl (meth) acrylate, β-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, etc. And an epoxy group-containing unsaturated monomer. (8): Perfluoroalkylethyl ester of acrylic acid or methacrylic acid such as perfluorobutylethyl (meth) acrylate, perfluoroisononylethyl (meth) acrylate, and perfluorooctylethyl (meth) acrylate (9): ethylene, propylene And olefins such as butylene and pentene. (10): Diene compounds such as butadiene, isoprene and chloroprene. (11): Fluoroolefins such as trifluoroethylene, tetrafluoroethylene, and vinylidene fluoride. (12): Vinyl esters and propenyl esters of fatty acids having 1 to 20 carbon atoms such as vinyl acetate, vinyl propionate, vinyl caprate, veoba monomer (manufactured by Shell Chemical Company, vinyl esters of branched higher fatty acids), and isopropenyl acetate. And vinyl ethers such as ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, butyl vinyl ether, octyl vinyl ether, cyclohexyl vinyl ether, phenyl vinyl ether and benzyl vinyl ether.

(13): acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, 2-carboxyethyl (meth) acrylate, 2-carboxypropyl (meth) acrylate, 5-carboxypentyl (meth) Carboxyl group-containing unsaturated monomers such as acrylates. (14): Hydrolysable alkoxysilyl group-containing unsaturated monomers such as vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (methoxyethoxy) silane, γ-methacryloyloxypropyltrimethoxysilane, and 2-styrylethyltrimethoxysilane. (15): Nitrogen-containing alkyl (meth) acrylates such as N, N-dimethylaminoethyl (meth) acrylate and Nt-butylaminoethyl (meth) acrylate. (16): acrylamide, methacrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-methylol (meth) acrylamide,
N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) Polymerizable amides such as acrylamide and diacetone acrylamide; 2-vinylpyridine, 1-
Nitrogen-containing monomers such as vinyl-2-pyrrolidone, 4-vinylpyridine and (meth) acryloylmorpholine. (17): Sulfonic acid monomers such as vinyl sulfonic acid, methallyl sulfonic acid, sulfoethyl (meth) acrylate, styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and salts thereof. (18): An esterified product of a hydroxyl group-containing monomer such as 2- (meth) acryloyloxyethyl acid phosphate and a phosphoric acid compound. (19): Phosphoric acid-containing monomers such as those obtained by adding a phosphoric acid compound to an epoxy group such as glycidyl (meth) acrylate. (20): Polymerizable nitriles such as acrylonitrile and methacrylonitrile. (21): a polymerizable amine such as allylamine. (22): Acid anhydride monomers such as maleic anhydride and itaconic anhydride. The content of the polyvinyl monomer in these monomer compositions is 1 to 15% by weight, preferably 2 to 1% by weight.
It must be 0% by weight. On the other hand, if the amount is less than 1% by weight, hyperbranching is insufficient, the viscosity of the resin cannot be reduced, the number of terminal functional groups is necessarily reduced, and the curability is reduced. On the other hand, if it is more than 15% by weight, it becomes easy to increase the molecular weight, and it becomes difficult to synthesize a resin having a low viscosity.

Next, a mercaptan used for introducing a molecular weight modifier and a terminal functional group in the present invention will be described.
In order to adjust the molecular weight of radical polymerization, a chain transfer agent is often used. Among them, mercaptan has a particularly high chain transfer constant and high chain transfer efficiency.
The used mercaptan will be incorporated into the molecular terminal since the polymerization reaction starts therefrom by chain transfer. It is also used industrially in a method of synthesizing a macromer utilizing this characteristic.

The mercaptan used in the present invention contains a hydroxyl group or a carboxyl group which can be generally used as a crosslinking functional group in a coating material.

Although the use of these mercaptans is a known technique, the feature of the present invention is that the number of terminals is increased by the use of a poly (vinyl monomer). Many groups are introduced. It is one of the intentions of the present invention to introduce many functional groups at the terminal of a molecule having high reactivity.

The mercaptan used in the present invention is not particularly limited as long as it contains a hydroxyl group or a carboxyl group, but a high molecular weight compound is not desirable for the purpose of the present invention. Specifically, for example, mercaptoethanol, thioglycerol, mercaptoacetic acid (thioglycolic acid),
Mercaptopropionic acid, thiomalic acid, thiosalicylic acid, and the like.

The amount of the compound used is not particularly limited, and an appropriate amount can be used depending on the amount of the initiator or the poly (vinyl monomer) used.

For example, by using n-1 mol of mercaptan with respect to n vinyl groups contained in the polyvinyl monomer-1 molecule used, the resin is effectively branched and functional groups are introduced into many terminals. It is thought to be done.

The polymerization method of the present invention is not particularly limited as long as it is a radical polymerization, but solution polymerization is preferred because the molecular weight can be easily reduced.

[0027] The polymerization temperature is from 20 ° C to 200 ° C, preferably from 50 ° C to 170 ° C. The initiator that can be used is not particularly limited as long as it is a radical polymerization initiator, and examples thereof include an azo initiator and a peracid value initiator.

The amount of the radical polymerization initiator used is, by weight ratio, mercaptan amount: radical polymerization initiator = 1: 0.1 to 1:
2, preferably 1: 0.2 to 1: 1.

If the polymerization initiator is used in a larger amount than the above ratio, the number of terminal functional groups intended in the present invention is undesirably reduced.

The solvent, reactive diluent and the like that can be used are not limited at all, and conventionally known solvents can be used.

The molecular weight of the acrylic resin thus obtained was measured by gel permeation chromatography (GPC), and the weight average molecular weight (Mw) was 5,000 to 2 in terms of polystyrene in terms of polystyrene.
000 and a ratio (M) to the number average molecular weight (Mn).
w / Mn) is required to be 3 to 8. Mw is 2
If it is larger than 0000, the viscosity of the resin becomes high, the suitability for high solids is lost, and the finish is reduced. If the weight average molecular weight is smaller than 5,000, curability and physical properties will be reduced. When Mw / Mn is smaller than 3, the branching is insufficient and the number of terminal functional groups is reduced, and the curability is reduced. On the other hand, when Mw / Mn is larger than 8, high solid suitability is lost. In the present invention, it is necessary that the molecular weight and the ratio of Mw / Mn fall within the above ranges by adjusting the amount of the polyvinyl monomer, the amount of the mercaptan, the amount of the initiator and the like.

[0032]

EFFECT OF THE INVENTION The acrylic resin for paint of the present invention can lower the resin viscosity by vigorous branching with a polyvinyl monomer. For this reason, it is possible to increase the solid content concentration of the paint, which is advantageous for high solidification.

The coating resin of the present invention has a good heat flow property, and as a result, a good finish. On the other hand, due to the effect of the functional group introduced at the hyperbranched terminal, the curability and physical properties of the coating film are good, and it is possible to reduce the viscosity of the resin and achieve these characteristics at the same time. That is, the present invention provides finishability,
Provide a resin for high solid paint having good curability and coating film properties.

[0034]

EXAMPLES The present invention will be described in detail with reference to examples.
“Parts” and “%” indicate “parts by weight” and “% by weight”, respectively. Example 1 Production Example of Acrylic Resin (NO.1) 460 parts of xylene and 120 parts of butyl acetate were added to a 5-liter reaction vessel equipped with a stirrer, a cooler, a temperature controller, a nitrogen inlet tube and a dropping funnel. , 600 parts of styrene, 240 parts of 2-ethylhexyl acrylate and 55 parts of 2-ethylhexyl methacrylate.
2 parts, 432 parts of 2-hydroxyethyl methacrylate,
Mixing of 360 parts of PLACSEL FM-3 (ε-caprolactone adduct of 2-hydroxyethyl methacrylate, trade name, manufactured by Daicel Chemical Industries, Ltd.), 24 parts of acrylic acid, and 120 parts of 1,6-hexanediol diacrylate The liquid and a mixed solution of 72 parts of azobisisobutyronitrile, 72 parts of mercaptoethanol, 210 parts of xylene, and 120 parts of ethyl acetate were added over 4 hours. After the addition,
The mixture was aged at 125 ° C. for 30 minutes, and then a mixture of 120 parts of xylene and 12 parts of azobis-2,4-dimethylvaleronitrile was added dropwise over 1 hour and 30 minutes. 69.0%, a light yellow transparent acrylic resin solution having a Gardner viscosity X and a resin acid value of 7.3 mg KOH / g. 1 was obtained. The molecular weight of this resin is M
w = 8800 and Mw / Mn = 3.67. The result of the heat flow test was 6.2 cm ² .

Sumidur N-3300 (hexamethylene diisocyanate tonurate type, manufactured by Sumitomo Bayer Urethane Co., Ltd.) was added to 30 parts of the above acrylic resin solution (NO. 1).
(Trade name) was added to prepare 8.8 parts of the paint of Example 1.

Example 2 The procedure of Example 1 was repeated except that the monomer mixture and the mercaptan mixture were the same as in Example 1. 2 was obtained.
Next, Sumidur N- was prepared in the same mixing ratio as in Example 1.
3300 was blended to prepare a coating material of Example 2.

Comparative Examples 1 and 2 Resin solution NO.
3, NO. 4 was obtained. Next, Sumidur N-3300 was blended at the same blending ratio as in Example 1, and Comparative Example 1,
A second paint was made.

[0038]

[Table 1]

Test method Heat flow: 0.5 g of a resin solution was dropped on a glass plate with a dropper.
After weighing g and drying at 100 ° C. for 30 minutes, the area where the resin spread was evaluated.

Preparation of Test Plate A dull steel plate subjected to a chemical conversion treatment was coated with a sample prepared with the following composition by an applicator. Dry it with a dryer 1
Baking was performed at 20 ° C. for 30 minutes to obtain a film thickness of 40 μm. Table 2 shows the physical properties of the coating itself.

[0041]

[Table 2]

Test Method Gel fraction: A sample having a thickness of 40 μm and dried at 120 ° C. for 30 minutes was cured at room temperature for 5 days. This coating film was extracted over 6 hours under reflux with acetone, dried and determined by weight change.

Gel fraction (%) = (weight of sample after extraction /
(Weight of sample before extraction) × 100 Tensile strength: The elongation percentage of the cured coating film was measured using Tensilon (“Tensilon UTN II-20”, trade name of Toyo Baldwin Co., Ltd.). The tensile speed was set at 20 ° C. and 4 mm / min, and the workability was evaluated by the average value of the elongation percentage of 10 samples. Curing start time: Leo Vibron DDV-OPAIII
The measurement was performed using a viscoelasticity meter manufactured by Orientec Co., Ltd. The relationship between the vibration period of the pendulum at the reference point and the heating time was examined and shown for each coating film. In this figure, the curing start time of each coating film was determined from the inflection point of the vibration period of the pendulum.

[Brief description of the drawings]

FIG. 1 is a schematic view of a molecular chain bonding model of a coating resin according to the present invention.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 29, 1999 (1999.6.2
9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0032

[Correction method] Change

[Correction contents]

The acrylic resin for paints of the present invention can lower the resin viscosity by vigorous branching with a polyvinyl monomer, and therefore, can increase the solid content concentration of the paints, thereby achieving high solids. It is advantageous.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction contents]

[0034]

EXAMPLES The present invention will be described in detail with reference to examples.
“Parts” and “%” indicate “parts by weight” and “% by weight”, respectively. Example 1 Production Example of Acrylic Resin (NO.1) 460 parts of xylene and 120 parts of butyl acetate were added to a 5-liter reaction vessel equipped with a stirrer, a cooler, a temperature controller, a nitrogen inlet tube and a dropping funnel. , 600 parts of styrene, 240 parts of 2-ethylhexyl acrylate and 55 parts of 2-ethylhexyl methacrylate.
2 parts, 432 parts of 2-hydroxyethyl methacrylate,
Mixing of 360 parts of PLACSEL FM-3 (ε-caprolactone adduct of 2-hydroxyethyl methacrylate, trade name, manufactured by Daicel Chemical Industries, Ltd.), 24 parts of acrylic acid, and 120 parts of 1,6-hexanediol diacrylate The liquid and a mixed solution of 72 parts of azobisisobutyronitrile, 72 parts of thioglycerol, 210 parts of xylene, and 120 parts of ethyl acetate were added over 4 hours. After the addition, 12
The mixture was aged at 5 ° C. for 30 minutes, and then a mixed solution composed of 120 parts of xylene and 12 parts of azobis-2,4-dimethylvaleronitrile was added dropwise over 1 hour and 30 minutes.
Maintained at 5 ° C., 69.0% solids, Gardner viscosity X,
Resin acid value 7.3 mgKOH / g pale yellow transparent acrylic resin solution NO. 1 was obtained. The molecular weight of this resin is Mw =
8800, Mw / Mn = 3.67. The result of the heat flow test was 6.2 cm ² .

Continued on the front page F-term (reference) 4J011 NA25 NB04 4J034 BA03 DA01 DA05 DB03 DB07 DB08 DD01 DP03 DP12 DP13 DP15 DP17 DP18 DP19 DP20 HA01 HA07 HC03 HC35 QA05 QB10 RA07 4J038 CA021 CB031 CB091 CB121 CC011 CC021 CC01 CC011 CC011 CC021 CG031 CG071 CG081 CG141 CG161 CG171 CH031 CH041 CH051 CH061 CH071 CH121 CH131 CH151 CH171 CH201 CH251 CK041 CL001 CR071 DB371 EA011 MA14

Claims (3)

[Claims] 1. A radically polymerizable unsaturated monomer component constituting a polymer having a polyvinyl monomer content of 1 to 15% by weight in the total monomer component, and a hydroxyl group as a chain transfer agent during polymerization. And / or a carboxyl group-containing mercaptan, the weight average molecular weight (Mw) of the produced polymer is 5,000 to 20,000, and the ratio between the weight average molecular weight (Mw) and the number average molecular weight (Mn) (Mw / Mn) is 3 to 8; 2. The polyvinyl monomer has a weight average molecular weight of:
The coating resin according to claim 1, which is in the range of 100 to 1,000. 3. The coating resin according to claim 1, wherein the mercaptan is at least one selected from mercaptoethanol, thioglycerol, mercaptoacetic acid and mercaptopropionic acid.