JPH11171942A - Urethane resin composition and molded product having gelcoat layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a urethane resin composition suitably usable as a gelcoat resin having excellent weathering resistance, and to obtain molded products having gelcoat layer using the above urethane resin composition. SOLUTION: This urethane resin composition comprises (A) a urethane(meth) acrylate obtained by reaction of a multifunctional isocyanate compound with a compound having an active hydrogen and an acryloyl group or mathacryloyl group, and if necessary, a dihydric alcohol, (B) a (meth)acrylate monomer, (C) a hindered amine-based compound having a group of the general formula I or II and (D) a compound having a structure of the general formula III. The other objective molded product having gelcoat layer is obtained by forming a gelcoat layer using the above urethane resin composition and forming a fiber- reinforced plastic layer or resin layer hereon. In the above formulas, R is a hydrogen atom or methyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a urethane resin composition having excellent weather resistance and suitable for forming a gel coat layer, and a molded article having the gel coat layer using the same.

[0002]

2. Description of the Related Art An FRP (fiber reinforced plastic) molded product is formed by applying a resin composition for a gel coat layer to a surface of a mold when molding using a mold, or onto a film surface when molding by a continuous molding line. ~ 0.5 mm in thickness and cured to form a gel coat layer, and on this layer a composition consisting of laminating resin such as unsaturated polyester resin and vinyl ester resin and glass fiber was laminated and cured Later, it is manufactured by demolding. Similarly, a composition composed of an unsaturated polyester resin and various fillers is poured into a mold on the gel coat layer, cured, and removed from the mold to obtain an artificial marble-like molded article. The gel coat layer is used for the purpose of decoration, protection, improvement of aesthetics, etc. of various molded articles. However, unsaturated polyester resins generally used as gel coat resins have been improved, but have a problem in weather resistance, and when exposed outdoors for a long time, decrease in gloss such as discoloration and chalking is relatively observed. It happens in a short time. For this reason, a molded article requiring weather resistance must be coated on the surface of the gel coat resin layer with a transparent paint such as a urethane paint composed of a urethane prepolymer and a polyol, or an acrylic paint, in order to prevent and protect discoloration. But,
These paints have a problem in that they have poor workability and harden and dry for a long time, resulting in poor productivity.

[0003]

The invention according to claims 1 to 3 has been made to solve the above-mentioned problems of the prior art, and is a urethane resin suitably used as a gel coat resin having excellent weather resistance. It provides a composition. The invention described in claim 4 provides a molded article having a gel coat layer using the urethane resin composition.

[0004]

That is, the present invention provides:
(A) a urethane (meth) acrylate obtained by reacting a polyfunctional isocyanate compound with a compound having active hydrogen and an acryloyl group or a methacryloyl group and, if necessary, a dihydric alcohol, (B) a (meth) acrylate ester A monomer, (C) a hindered amine compound having a group of the general formula (1) or (2), and

Embedded image (Wherein R represents a hydrogen atom or a methyl group) (D) a compound having the structure of general formula (3)

Embedded image (Wherein, R represents a hydrogen atom or a methyl group).

[0005] The present invention also relates to the urethane resin composition wherein the polyfunctional isocyanate compound used in the synthesis of the component (A) is an aliphatic diisocyanate and / or an alicyclic diisocyanate. Further, the present invention relates to (A)
The present invention relates to the urethane resin composition, wherein the polyfunctional isocyanate compound used in the synthesis of the component is a trimer of an aliphatic diisocyanate and / or an alicyclic diisocyanate represented by the general formula (4) or (5).

Embedded image (Wherein, R represents an aliphatic or alicyclic alkylene group having 6 to 20 carbon atoms)

The present invention also relates to a molded article having a gel coat layer formed by using any one of the above urethane resin compositions and forming a fiber reinforced plastic layer or a resin layer thereon.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The urethane (meth) acrylate of the component (A) of the present invention is obtained by reacting a polyfunctional isocyanate compound with active hydrogen, a compound having an acryloyl group or a methacryloyl group and, if necessary, a dihydric alcohol. It can be obtained by: Examples of the polyfunctional isocyanate compound include diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, and 2,2,4-trimethyl hexaisocyanate. Methylene diisocyanate, cyclohexylmethane diisocyanate,
Two or more isocyanates such as methylcyclohexane diisocyanate, isopropylidene bis (4-cyclohexyl isocyanate), hexamethylene diisocyanate, a buret of hexamethylene diisocyanate, a trimer of isophorone diisocyanate containing an isocyanurate ring, and polymethylene polyphenyl polyisocyanate. Group-containing compounds, polyhydric alcohols such as trimethylolpropane, glycerin and pentaerythritol (n
A compound obtained by reacting the diisocyanate compound with n moles per mole of the diisocyanate compound is used.

Further, a trimer of an aliphatic diisocyanate and / or an alicyclic diisocyanate represented by the general formula (4) or (5) is also used.

Embedded image (In the formula, R represents an aliphatic or alicyclic alkylene group having 6 to 20 carbon atoms.)

Among them, trimerized polyisocyanates represented by the general formula (4) or (5) using hexamethylene diisocyanate as a starting material are preferable in terms of flexibility and hardness. The polyisocyanate obtained by trimerizing hexamethylene diisocyanate can be easily obtained from the market. For example, Asahi Kasei Kogyo Co., Ltd., Duranate 24A-100 (Bullet type), Duranate TPA-100 (with isocyanurate ring) Including). Examples of polyfunctional isocyanate compounds obtained by reacting 1 mol of trimethylolpropane with 3 mol of tolylene diisocyanate include Coronate L and HL (trade names of Nippon Polyurethane Industry Co., Ltd.).

The compound having active hydrogen and an acryloyl or methacryloyl group is hydroxy (meth) acrylate [(meth) acrylate means methacrylate or acrylate. ] Is preferably used. Examples of the hydroxy (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 2-hydroxyalkyl (meth) acrylate such as 2-hydroxypropyl (meth) acrylate, and among these, 2-hydroxyethyl methacrylate is It is preferable in terms of reactivity and economy.

The dihydric alcohol to be reacted as required includes ethylene glycol, propylene glycol,
1,6-hexanediol, diethylene glycol, triethylene glycol, 1,4-butanediol, 1,
8-octanediol, 1,9-nonanediol, 1,
Examples thereof include aliphatic and / or alicyclic polyalkylene glycols having 2 to 20 carbon atoms, such as 10-decanediol and 1,4-cyclohexanediol. Among them, it is preferable to balance the flexibility and the hardness of the coating film obtained having 2 to 12 carbon atoms.

As a condition for obtaining a urethane acrylate (A) by reacting a polyfunctional isocyanate compound with an active hydrogen, a compound having an acryloyl group or a methacryloyl group, and a dihydric alcohol to be added as required, the reaction temperature is usually 0. To 120 ° C, preferably 20 to 80 ° C, and the reaction time is usually 1 to 50 hours, preferably 3 to 1 hour.
0 hours. In the reaction, a urethane reaction catalyst such as dibutyltin dilaurate and a polymerization inhibitor such as hydroquinone, methylhydroquinone and N-nitrosophenylhydroxylamine aluminum salt may be present. All of these materials may be reacted simultaneously, by reacting any compound with a polyfunctional isocyanate compound,
Next, another compound may be reacted.

The ratio of the starting monomers used is 0.8 to 1. The total amount of the active hydrogen of the compound having an active hydrogen and an acryloyl group or a methacryloyl group and the active hydrogen of a dihydric alcohol with respect to the isocyanate group of the polyfunctional isocyanate compound.
It is preferred to be in the range of 5 equivalents. More preferably, it is in the range of 0.9 to 1.2 equivalents. Further, the compound having active hydrogen and an acryloyl group or a methacryloyl group and the dihydric alcohol have a total amount of both active hydrogens of 100 equivalent% and a compound having an active hydrogen and an acryloyl group or a methacryloyl group of 100 to 60 equivalent%. It is preferable to use the dihydric alcohol in the range of 0 to 40% by weight. More preferably, the compound having the active hydrogen and an acryloyl group or a methacryloyl group is 100 to 80.
% Of the above-mentioned dihydric alcohol is in the range of 0 to 20 equivalent%.

[0014] The (meth) component (B) used in the present invention.
As the acrylate monomer, for example, methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, Dicyclopentenyl (meth) acrylate, 2-dicyclopentenoxyethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, methoxyethoxyethyl (meth) acrylate, Ethoxyethoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyrate Le (meth) acrylate, (meth) acryloyl morpholine and the like, and polyfunctional (meth) acrylate may also be used. Specific examples of the polyfunctional (meth) acrylate include trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, polypropylene glycol di (meth) acrylate, and polyethylene glycol di (meth) acrylate. These (meth) acrylate monomers are appropriately selected depending on the physical properties of the target coating film and the curability at the time of molding, and one or two or more monomers may be used in combination.

The hindered amine compound having the structure of the general formula (1) or (2) of the component (C) used in the present invention includes, for example, bis (2,2,6,6-tetramethylpiperidinyl- 4-sebacate), dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidyl succinate, poly [{6- (1,1,3,3) -Tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene} (2,2,6 6-tetramethyl-4-piperidyl) imino}], 2- (3,5
-Di-t-butyl-4-hydroxybenzyl) -2-n
Bis (1,2,2,6,6-pentamethyl-4-piperidyl) -butylmalonate, N, N'-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- ( 1,2,2,6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, bis (1,2,2,6,6-pentamethyl-4-piperidinyl) ) Sebacate and the like. Among the above components (C), in particular, bis (1, 2, 2,
(6,6-Pentamethyl-4-piperidinyl) sebacate is preferred, but these can be used alone or in combination of two or more.

The compound (D) having the structure of the general formula (3) is not particularly limited. Examples of compounds that can be easily obtained as commercial products include, for example, R
UVA-93 can be mentioned. By using the hindered amine compound having the structure of the general formula (1) or (2) of the component (C) in combination with the component (D) of the compound having the structure of the general formula (3), weather resistance is improved, Chalking and blistering can be suppressed. The addition amount of the compound having the structure of the general formula (1) or (2) is preferably 0.01 to 10% by weight, particularly preferably 0.1 to 5% by weight in the resin composition. Also,
The amount of the component (D) added is preferably 0.0
It is 5 to 20% by weight, particularly preferably 0.1 to 10% by weight.

The urethane resin composition of the present invention can be prepared by using known metal soaps such as cobalt naphthenate and cobalt octenoate, quaternary ammonium salts such as dimethylbenzylammonium chloride, β-diketones such as acetylacetone, dimethylaniline, N -Ethyl-meta toluidine,
Curing can be performed by a combination of a curing accelerator such as an amine such as triethanolamine and an organic peroxide, and depending on the selection of the organic peroxide, curing can be performed by heating at a temperature in the range of 30 to 200 ° C. Organic peroxides include cumene hydroperoxide, tertiary butylperoxy 2-ethylhexanate, tertiary hexylperoxy 2-ethylhexanate, methyl ethyl ketone peroxide, benzoyl peroxide, acetylacetone peroxide, bis-4- Tertiary butyl cyclohexane dicarbonate and the like may be mentioned, and two or more of these may be used in combination.

In the urethane resin composition of the present invention, a known ultraviolet absorber can be used if necessary. For example, 2-hydroxy-4-methoxybenzophenone, 2
-Hydroxy-4-octyloxybenzophenone, 2
-Hydroxy-4-decyloxybenzophenone, 2-
Hydroxy-4,4'-dimethoxybenzophenone, 2
Derivatives of 2-hydroxybenzophenone such as -hydroxy-4,4'-dibutoxybenzophenone, or 2
-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-
Ditert-butylphenyl) benzotriazole, 2
-(2'-hydroxy-3 ', 5'-bis (2,2'-
Examples thereof include dimethylpropyl) phenyl) benzotriazole or halides thereof, and esters of salicylic acid such as phenyl salicylate and p-tert-butylphenyl salicylate. These can be used alone or in combination of two or more. Further, if necessary, polymerization inhibitors such as hydroquinone, toluhydroquinone, tertiary butyl catechol, hydroquinone monomethyl ether, dyes,
Various additives such as known thixotropic agents such as pigments, plasticizers, and silica powder, stabilizers, defoamers, and leveling agents can be blended.

The molded article having a gel coat layer according to the present invention is obtained by curing the gel coat layer in advance and then, if necessary, laminating and casting an unsaturated polyester resin (for example, Hitachi Chemical Co., Ltd.) together with glass fiber and an inorganic filler. Industrial Co., Ltd.
Made, trade name Polyset-5595APT, Polyset-
T4520) or a resin by a known method,
After curing, it is obtained by demolding. When molding using a mold, the gel coat layer is applied to the mold surface, and in continuous molding, etc., is applied to a film of cellophane, polyethylene, polypropylene, polyethylene terephthalate, etc.
After curing, the resin for lamination and casting is laminated, cast, cured, and then demolded. There is no limitation on the laminating and casting resins to be used, and known radically polymerizable resins such as orthophthalic unsaturated polyester, isophthalic unsaturated polyester, vinyl ester resin and urethane acrylate are used. Examples of the glass fiber include a chopped strand mat, a spray roving, a roving cloth, a continuous strand mat, a surfacing mat, a preformable mat, a chopped fiber direct preform, and the like. These may be used in combination of two or more.

As the inorganic filler, talc, mica, kaolin calcium carbonate, aluminum hydroxide,
Examples include clay, ceramic powder, alumina, and glass beads. These may be used in combination of two or more. The curing of the casting resin for lamination may be performed at room temperature or by heating, and the organic peroxide used in the urethane resin composition described above is used. These may be used in combination of two or more. The gel coat layer is applied to one or both surfaces of the molded article, or part or all of the surface, and is not particularly limited.

[0021]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. Parts and% in the examples represent parts by weight and% by weight, respectively.

Synthesis Example 1 <Synthesis of urethane acrylate (I)> A 1-liter four-necked flask equipped with a stirrer, a cooler, a thermometer and a dropping funnel was charged with a hexamethylene diisocyanate-based buret-modified trifunctional polyisocyanate compound. (Asahi Chemical Industry
(Duranate-24A-100) 450 parts and methyl methacrylate 210 parts were charged, and hydroquinone 0.5
g and 2 g of dibutyltin laurate were added and heated to 60 ° C. Then, 330 parts of 2-hydroxyethyl methacrylate, 10 parts of ethylene glycol 10
Of the mixed solution was added dropwise over 4 hours. During the synthesis, the reaction was traced using an infrared spectrophotometer, and the disappearance of the absorption peak near 2440 cm ⁻¹ due to the isocyanate group was defined as the synthesis end point. In Synthesis Example 1, 1
The synthesis was terminated because the absorption peak had disappeared by measuring the time. A colorless and transparent urethane acrylate (I) having a viscosity of 10 poise at 25 ° C. was obtained.

Synthesis Example 2 <Synthesis of urethane acrylate (II)>
00 parts, 238 parts of methyl methacrylate, 0.5 part of hydroquinone, and 2 parts of dibutyltin laurate were charged into a 1-liter flask and heated to 60 ° C. Next, a mixed solution of 450 parts of 2-hydroxyethyl methacrylate and 14 parts of propylene glycol was added dropwise over 4 hours. The synthesis end point was confirmed with an infrared spectrophotometer as in Synthesis Example 1.
A colorless and transparent urethane acrylate (II) having a viscosity of 4.0 poise at 25 ° C. was obtained.

Synthesis Example 3 <Synthesis of unsaturated polyester resin> 788 parts of phthalic anhydride and 33 of fumaric acid were placed in a two-liter four-necked flask equipped with a stirrer, a condenser, a nitrogen gas inlet tube and a thermometer.
3 parts, 724 parts of neopentyl glycol and 155 parts of propylene glycol were charged, and the temperature was raised to 150 ° C. for 1 hour using a mantle heater while passing nitrogen gas, and further raised to 215 ° C. for 6 hours. The reaction proceeded while keeping the temperature at that temperature to obtain an unsaturated polyester having an acid value of 20. Into this, 0.01% of methylhydroquinone was dissolved in a styrene monomer in which the unsaturated polyester content was 62% to obtain an unsaturated polyester resin having a viscosity at 25 ° C. of 0.45 (Pa · s).

Examples 1 to 4 and Comparative Examples 1 to 3 For a gel coat prepared according to the composition shown in Table 1 on a glass plate of 30 cm in length, 30 cm in width and 10 mm in thickness on which a polyethylene terephthalate film having a thickness of 0.05 mm was stuck. The urethane resin composition and the unsaturated polyester resin composition were each applied to a thickness of 0.05 mm using an applicator, and were mixed at 120 ° C. for 1 minute or 50 ° C. for 4 minutes depending on the compounding.
It was cured in a thermostat for 0 minutes to form a gel coat layer.

Next, on this gel coat layer, 30 × 30
² sets of chopped strand mat (weight per unit 450 g / m ² ) manufactured by Nitto Boseki Co., Ltd.
(Unsaturated polyester resin manufactured by Hitachi Chemical Co., Ltd.) 10
A resin composition for lamination containing 1 part of Permec N (trade name, manufactured by NOF CORPORATION, organic peroxide, 55% methyl ethyl ketone peroxide) per 0 parts so that the glass content is 30% by weight. After impregnating and curing at 50 ° C. for 40 minutes, it was cooled and demolded to obtain an FRP molded product. The properties of the obtained gel coat layer and FRP molded product were examined as follows, and the results are shown in Table 2.

(1) Weather resistance: The thickness of the gel coat is set to 0.0
An acceleration test was performed with a sunshine weatherometer (manufactured by Suga Test Instruments Co., Ltd.) on an FRP molded product having a constant thickness of 5 mm, and the occurrence of chalking and the color difference were examined as follows. i) Occurrence of chalking: The occurrence time of chalking was confirmed by irradiating a sunshine weatherometer. ii) Yellowing degree (ΔYI): JIS-K-71 shows the change in color when irradiated with a sunshine weatherometer for 1000 hours.
The measurement was performed using a # 90 color difference meter manufactured by Nippon Denshoku Industries Co., Ltd. (2) Heat cycle property After heating at 80 ° C. for 1 hour, it was immersed in an acetone-dry ice solution at −20 ° C. for 1 hour, and the state of cracks on the gel coat surface when this was repeated four times was observed.

(3) Water Adhesion Resistance As in the crocut tape method of the adhesion test specified in JIS-K-5400, a length of about 40 mm which intersects the gel coat surface at an angle of 30 degrees and reaches the laminated resin layer. A cut was made. Approximately 5 only on the cut gel-coated surface
The time until the peeling between the gel coat layer and the laminated resin layer was measured with hot water of 0 ° C. being applied. (4) Hardness The hardness of the gel coat layer was measured based on the pencil hardness specified in JIS-K-5400. (5) Gloss The gloss of the surface of the gel coat was measured at 60 ° specular gloss according to JIS-K-7105.

[0029]

[Table 1]

[0030]

[Table 2]

From the results shown in Table 2, it can be seen that the molded article having the gel coat layer using the urethane resin composition of the present invention has better weather resistance, heat cycle property and adhesion than the conventional weather resistant unsaturated polyester resin composition. Excellent, showing improved hardness and gloss.

[0032]

According to the urethane resin composition according to the first to third aspects, the FR installed outdoors can be improved in weather resistance life.
A gel coat layer capable of preventing the deterioration of the appearance of the P molded product can be formed. The molded article having the gel coat layer according to claim 4 can improve the quality because the surface hardness and glossiness are improved.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08F 220: 36)

Claims (4)

[Claims] 1. A urethane (meth) acrylate obtained by reacting (A) a polyfunctional isocyanate compound with an active hydrogen and a compound having an acryloyl group or a methacryloyl group and, if necessary, a dihydric alcohol, (B)
(Meth) acrylic acid ester monomer, (C) a hindered amine compound having a group represented by formula (1) or (2), and (Wherein R represents a hydrogen atom or a methyl group) (D) a compound having the structure of general formula (3) (Wherein, R represents a hydrogen atom or a methyl group). 2. The polyfunctional isocyanate compound used in the synthesis of the component (A) is an aliphatic diisocyanate and / or an aliphatic diisocyanate.
Or the urethane resin composition according to claim 1, which is an alicyclic diisocyanate. 3. The polyfunctional isocyanate compound used in the synthesis of the component (A) is a trimer of an aliphatic diisocyanate and / or an alicyclic diisocyanate represented by the general formula (4) or (5). 2. The urethane resin composition according to 1. Embedded image (Wherein, R represents an aliphatic or alicyclic alkylene group having 6 to 20 carbon atoms) 4. A molded article having a gel coat layer formed by forming a gel coat layer using the urethane resin composition according to claim 1 and forming a fiber reinforced plastic layer or a resin layer thereon. .