JP2931118B2 - Curing method of urethane (meth) acrylate liquid resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for curing a liquid urethane (meth) acrylate resin. Various liquid resins typified by unsaturated polyesters are cured by various methods, and various curing agents such as radical initiators and curing accelerators are used for curing. The formulation of such curing agents, in light of the practice of industrial curing molding operations,
In relation to the time until the curing of the liquid resin starts (hereinafter referred to as curing start time), the time required for completing the curing (hereinafter referred to as curing completion time), and the curing behavior such as the maximum attainable temperature based on the heat generated by curing. It is important that decisions be made. The present invention provides a urethane (meth) acrylate comprising a urethane (meth) acrylate and a vinyl monomer copolymerizable with the urethane (meth) acrylate, which is characterized by the formulation of a curing agent.
The present invention relates to a method for curing an acrylate liquid resin.

[0002]

2. Description of the Related Art Conventionally, in the field of unsaturated polyester,
The liquid resin, using an organic peroxide as a radical initiator,
It is also known to cure using a curing agent formulated with cobalt naphthenate as a curing accelerator. However,
A curing agent having such a formulation is described in, for example, JP-A-57-18231.
2 and the use of the resin for curing urethane (meth) acrylate liquid resin as described in JP-A-61-225210, the curing start time and the curing completion time are extremely long. It will almost disappear.

[0003] In the field of unsaturated polyesters, the liquid resin is formed by using diacyl peroxide as a radical initiator,
It is also known that curing is carried out at room temperature using a curing agent formulated with an aromatic tertiary amine as a curing accelerator. However, when the curing agent having such a formulation is used for curing the urethane (meth) acrylate liquid resin, the curing start time and the curing completion time are extremely short, and the curing starts almost at the same time as the liquid resin is filled into the mold. Since the curing is completed on the way, industrial application becomes extremely difficult.

For the curing of urethane (meth) acrylate liquid resin, the amount of a curing agent formulated using diacyl peroxide as a radical initiator and an aromatic tertiary amine as a curing accelerator can be reduced, Alternatively, a desired effect cannot be obtained even when a quinone-based radical inhibitor that is effective for inhibiting a radical reaction is used in combination. Curing agents of formulations conventionally known in the field of unsaturated polyesters increase the onset of cure of urethane (meth) acrylate liquid resins to the time required from the practice of industrial cure molding operations, while The two conditions of shortening the curing completion time from the industrial advantage to the required time cannot be satisfied at the same time.

[0005]

The problem to be solved by the present invention is that a curing agent having a conventionally known formulation has a curing start time of an industrial curing time when a urethane (meth) acrylate liquid resin is cured. The point is that the two conditions of lengthening the time required from the actual operation of the molding operation to the time required for curing while shortening the time required for completing the curing to the required time from the industrial advantage cannot be satisfied.

[0006]

SUMMARY OF THE INVENTION The present invention provides a method for radically curing a urethane (meth) acrylate liquid resin comprising a urethane (meth) acrylate and a vinyl monomer copolymerizable with the urethane (meth) acrylate. 1) organic peroxides, 2) aromatic tertiary amines,
3) A substance capable of forming a covalent valence bond with the lone pair of electrons of the aromatic tertiary amine (hereinafter referred to as a covalent valence bond forming substance), and the above three components 1) to 3) coexist. Or 4) an organic peroxide, 5) a coordination compound based on a covalent valence bond between an aromatic tertiary amine and a covalent valence bond-forming substance, and the above two components 4) and 5) coexist. And a method for curing a urethane (meth) acrylate liquid resin.

The organic peroxide which is a radical initiator used in the present invention includes: 1) dilauroyl peroxide, dibenzoyl peroxide, and substituted benzoyl peroxide having a substituent such as a methyl group or a methoxy group on an aromatic group. 2) alkyl peroxycarboxylates such as t-butyl peroxy octoate and t-butyl peroxy benzoate, 3) dicumyl peroxide, di-t-butyl peroxide, 1,1 −
Diallyl peroxides such as bis (t-butylperoxy) -3,3,5-trimethylcyclohexane and dialkyl peroxides; 4) t-butylperoxy-2-
And peroxycarbonates such as ethylhexyl carbonate.

The aromatic tertiary amine which is a curing accelerator used in the present invention includes N, N-dimethylaniline,
There are known compounds such as N, N-dimethyl-p-toluidine.

Further, as the covalent valence bond forming substance used in the present invention, a Lowry-Bronsted acid defined by Lowry and Bronsted (TM Lowry, Chemistry and Industry, Vol. 42, p. 43, 1923)
Year, JN Brφnsted, Rec.trav. Chim, 42, 71
8, 1923), and in a broader sense Lewis acids defined by Lewis (GN Lewis, J. Franklin lnst, 226).
Vol. 293, 1938). Laurie-Bronsted acids and Lewis acids are substances capable of forming a covalent valence bond with the lone pair of electrons possessed by the aromatic tertiary amine, that is, covalent valence bond forming substances.

[0010] Specifically, there are various inorganic acids and organic acids as the Laurie-Bronsted acid. Laurie-Brönsted acid has a property capable of donating a proton to an aromatic tertiary amine. The absolute strength of such properties depends on the type of medium in which they are present, but usually the acidity of Laurie-Bronsted acid is one indicator. Specifically, for example, a common logarithmic value pka of the reciprocal of the dissociation constant at 25 ° C. of the Laurie-Bronsted acid in an aqueous medium can be used as an index. The Lowry-Brönsted acids that can be advantageously used in the present invention include: 1) trichloroacetic acid (pka = 0.66), oxalic acid (pka = 1.04), and maleic acid (pka = 1.7).
5) carboxylic acids such as 2) monobutyl acid phosphoric acid (p
ka = 1.6), methanesulfonic acid (pka = 1.2)
6), organic acids such as paratoluenesulfonic acid (pka = 1.55), 3) sulfuric acid (pka = 1.99), nitric acid (p
Inorganic acids such as ka = 1.8) and those having a pka value at 25 ° C. in an aqueous medium of less than 2.7 in an aqueous medium such as ka = 1.8).

The Lewis acids not included in the Lowry-Bronsted acid include boron trifluoride, zinc chloride, tin chloride, aluminum chloride, and various types of acid clay.

The coordination compound used in the present invention is a salt in which the above-mentioned aromatic tertiary amine is covalently bonded to a covalent bond-forming substance, for example, Laurie-Brönsted acid.

The amount of the curing agent used in the formulation of the present invention is not particularly limited, but the amount of the organic peroxide is 0.5 to 2 parts by weight based on 100 parts by weight of the urethane (meth) acrylate liquid resin, The tertiary amine is used in an amount of 0.01 to 1.0 part by weight based on 100 parts by weight of the urethane (meth) acrylate liquid resin. Is preferred.
When a coordination compound is used, it is preferable that the coordination compound is substantially the same as the aromatic tertiary amine.

The urethane (meth) acrylate liquid resin to which the curing method of the present invention is applied comprises a urethane (meth) acrylate, that is, a carbon-carbon unsaturated double bond comprising a (meth) acryloyl group in a molecule and a urethane bond. And a liquid monomer comprising a vinyl monomer copolymerizable with the urethane (meth) acrylate.

Examples of the urethane (meth) acrylate include Group A: urethanization products of 2-hydroxyalkyl (meth) acrylate and a polyisocyanate or a polyurethane polyisocyanate having two or more isocyanate groups in a molecule, Group B : (Meth) acrylic acid and 3
Urethanization product of a (meth) acrylate monol and isocyanate derived from a polyhydric alcohol having a valency of 3 or more or a polyol having 3 or more hydroxyl groups in the molecule, Group C: the above (meth) acrylic acid Ester monool and 2-hydroxyalkyl (meth) acrylate as a hydroxy component, a urethane product of these and a polyisocyanate, Group D: (meth) acrylic acid 2-
There are urethane products of isocyanatoethyl and dihydric or higher polyhydric alcohols or polyols having two or more hydroxyl groups in the molecule.

Specifically, those belonging to Group A include 3.5 moles of 2-hydroxyethyl methacrylate and polymethylene polyphenyl polyisocyanate (NCO
1 mole of urethanation product (containing 3.5 groups on average) (molecular number of double bonds 3.5, molecular weight 25 per double bond)
8). Further, those belonging to the group B include a urethane product of 2 mol of glycerin dimethacrylate and 1 mol of tolylene diisocyanate (the number of double bonds is 4.0,
There is a molecular weight of 158) per double bond. Further, the C
As a member of the group, a urethanization product of 1 mol of glycerin dimethacrylate, 1 mol of 2-hydroxyethyl methacrylate and 1 mol of tolylene diisocyanate (the number of double bonds is 3.0, the molecular weight per double bond is 17)
7). As a material belonging to the group D, there is a urethane product of 1 mol of glycerin and 3 mol of 2-isocyanatoethyl methacrylate (the number of double bonds is 3.0, and the molecular weight per double bond is 186).

The vinyl monomers copolymerizable with urethane (meth) acrylate include: 1) (meth) such as methyl acrylate, ethyl acrylate, isopropyl acrylate, methyl methacrylate, ethyl methacrylate, and isopropyl methacrylate; Lower alkyl acrylate, 2) aromatic vinyl monomer such as styrene, α-methylstyrene, divinylbenzene, 3) halogen such as brominated styrene, tetrabromobisphenol A dimethacrylate, polyethoxylated tetrabromobisphenol A dimethacrylate, etc. Aromatic derivatives and the like. These vinyl monomers can be used alone or in combination of two or more.
Among them, it is preferable to use methyl methacrylate or styrene.

The ratio of urethane (meth) acrylate to vinyl monomer in the urethane (meth) acrylate liquid resin is not particularly limited, but usually urethane (meth) acrylate / vinyl monomer = 10/90 to 90/10
(Weight ratio), preferably 40/60 to 75/25
(Weight ratio).

In the present invention, a known inorganic powdery filler such as calcium carbonate or aluminum hydroxide can coexist in the urethane (meth) acrylate liquid resin. Although the amount of the inorganic powdery filler is not particularly limited, it is usually 10 per 100 parts by weight of the urethane (meth) acrylate liquid resin.
0 parts by weight or less.

The molding method to which the present invention is applied is not particularly limited, but a particularly advantageous molding method is a resin transfer molding method (hereinafter referred to as RTM) or a reaction injection molding method (hereinafter referred to as RI).
M). As one method of curing and molding by applying RTM or RIM, a urethane (meth) acrylate liquid resin in which predetermined amounts of an aromatic tertiary amine and a covalent bond-forming substance are mixed and dissolved, respectively, and a radical initiator Using a solution, these can be transferred by a metering pump so as to have a predetermined ratio, mixed by a static mixer, and then injected and transferred into a mold to be cured and molded in the mold.

As another method, a urethane (meth) acrylate liquid resin in which a predetermined amount of a covalent valence bond-forming substance is mixed and dissolved, and a urethane (meth) acrylate liquid in which a predetermined amount of an aromatic tertiary amine is mixed and dissolved. Using a resin and a radical initiator solution, curing and molding can be performed in the same manner as described above. In either method, a liquid resin or the like can be injected and transferred into a mold loaded with reinforcing fibers such as a glass fiber mat. The mold temperature when applying RTM or RIM is not particularly limited, but is usually 20
To 70 ° C, preferably 30 to 60 ° C.

According to the present invention, 1) an organic peroxide, 2)
Aromatic tertiary amines, 3) covalent bond-forming substances,
By coexisting the above three components 1) to 3), or 4) an organic peroxide, 5) a coordination compound based on a covalent valence bond between an aromatic tertiary amine and a covalent valence bond forming substance By coexisting the above two components 4) and 5), the curing start time of the urethane (meth) acrylate liquid resin is extended to the time required from the actual practice of an industrial curing molding operation, while curing is performed. The two conditions of shortening the completion time from the industrial advantage to the required time can be satisfied together.

<Examples> Test section 1 1) Preparation of urethane methacrylate liquid resin A In a flask, add Millionate MR-100 (polymethylene polyphenyl polyisocyanate containing an average of 3.5 isocyanate groups per molecule, Nippon Polyurethane) 1)
09.6 parts (parts by weight, the same applies hereinafter), 148.2 parts of methyl methacrylate, and 0.1 part of di-n-butyltin dilaurate.
9 parts were taken, stirred at 50 ° C., and 112.7 parts of hydroxyethyl methacrylate was added dropwise over 15 minutes. At this time, the reaction heat is generated.
It was kept below 0 ° C. Thereafter, the temperature was maintained at 60 ° C. for 1 hour to complete the synthesis. Urethane methacrylate liquid resin A containing 60% urethane methacrylate (% by weight, the same applies hereinafter)
I got

2) Preparation of Urethane Methacrylate Liquid Resin C Coronate T-80 (2,4- and 2,6-
87.1 parts of mixed tolylene diisocyanate (manufactured by Nippon Polyurethane), 264.6 parts of methyl methacrylate and 0.9 part of di-n-butyltin dilaurate
The mixture was stirred while maintaining the temperature at 0 ° C., and 65.0 parts of hydroxyethyl methacrylate and glycerin dimethacrylate 11
4.1 parts were added dropwise over 20 minutes. At this time, heat of reaction was generated, but the temperature in the flask was kept at 55 to 60 ° C. Thereafter, the temperature was maintained at 60 ° C. for 1.5 hours to complete the synthesis. A urethane methacrylate liquid resin C containing 60% urethane methacrylate was obtained.

3) Preparation of urethane methacrylate liquid resin D 235.9 parts of 2-isocyanatoethyl methacrylate,
Using 200 parts of methyl methacrylate, 0.9 parts of di-n-butyltin dilaurate, and 43.3 parts of glycerin, a urethane methacrylate liquid resin D containing 60% by weight of urethane methacrylate was prepared in the same manner as in the preparation of the urethane methacrylate liquid resin A. Obtained.

Test Category 2 1) Examples 1 to 9 and Comparative Examples 1 to 4 To 100 parts by weight of the urethane methacrylate liquid resin A at 25 ° C. prepared in Test Section 1 were added 0.02 parts by weight of dimethyl paratoluidine and Table 1 The stated amount of covalent valence bond forming material was added and homogenized. A sample in which 1 part by weight of dibenzoyl peroxide was added and dissolved was transferred to a test tube, and immediately left in a constant temperature bath at a bath temperature of 50 ° C. The time required for the sample temperature to reach from 25 ° C. to 55 ° C. (t ₁ ), the time required for the sample temperature to reach from 25 ° C. to the maximum temperature based on the heat generated by curing (t ₂ ) and reached The maximum temperature (T) was measured.

As a comparative example, the same operation as described above was carried out for the case where no covalent valence bond forming substance was added and the case where a known radical polymerization inhibitor hydroquinone was added instead of the covalent valence bond forming substance. ,It was measured. Table 1 shows the measurement results. Here, t ₁ is the curing start time (so-called gel time), and t ₂ is the curing completion time (so-called cure time).

[0028]

[Table 1]

Note) In Table 1, (3): Covalent valence bond forming substance * 1: No exothermic peak is observed even after elapse of 20 minutes * 2: The liquid temperature reaches 55 ° C. even after elapse of 20 minutes * 3: Exothermic peak is observed, but curing is not completed even after 20 minutes. * 4: No exothermic peak is observed after 20 minutes, and curing is not completed. the same

2) Examples 10 to 13 and Comparative Examples 5 to 9 100 parts by weight of the urethane methacrylate liquid resin C at 25 ° C. prepared in Test Category 1 were charged with a predetermined amount of dimethyl paratoluidine and a covalent bond shown in Table 2. Forming material was added to homogenize. Using a sample in which 1 part by weight of dibenzoyl peroxide was added and dissolved therein,
The operation was performed in the same manner as in the case of No. 9, and the measurement was performed.

In addition, as a comparative example, the same operation as described above was carried out for a sample in which the use ratio of dimethyl paratoluidine and dibenzoyl peroxide was changed without adding a covalent valence bond-forming substance. Table 2 shows the measurement results.

[0032]

[Table 2]

Note) In Table 2, (1): dibenzoyl peroxide (2): dimethyl paratoluidine

3) Examples 14 and 15 and Comparative Example 10 Using 100 parts by weight of the urethane methacrylate liquid resin D prepared at 25 ° C. in Test Category 1 and using a curing agent having the formulation shown in Table 3, the following Example 1 was used. The operation was performed in the same manner as in the case of No. 9 to No. 9, and the measurement was performed. The results are shown in Table 3.

4) Examples 16 to 18 and Comparative Example 11 Based on 100 parts by weight of the urethane methacrylate liquid resin A at 25 ° C. prepared in Test Category 1, 0.02 parts by weight of dimethyl paratoluidine and curing of the formulation described in Table 3 Using the agent, operation and measurement were performed in the same manner as in Examples 1 to 9 below. The results are shown in Table 3. The dimethyl paratoluidine acid sulfate used in Example 15 corresponds to the coordination compound in the present invention, and the covalent valence bond forming substance used in Examples 16 and 17 corresponds to Lewis acid. .

[0036]

[Table 3]

Note) In Table 3, (5): dimethyl paratoluidine acid sulfate a: sulfuric acid b: aluminum chloride c: boron trifluoride ether complex

[0038]

As is apparent from the above description, the present invention described above makes it possible to extend the curing start time of a urethane (meth) acrylate liquid resin to the time required from the actual practice of an industrial curing molding operation. On the other hand, there is an effect that both conditions of shortening the curing completion time to the required time from the industrial advantage can be satisfied.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-193914 (JP, A) JP-A-52-140590 (JP, A) JP-A-58-29813 (JP, A) JP-A-57-1983 182312 (JP, A) JP-A-51-137797 (JP, A) JP-A-52-42593 (JP, A) JP-A-4-132715 (JP, A) JP-A-63-162705 (JP, A) JP-A-61-225210 (JP, A) JP-A-55-125117 (JP, A) JP-A-4-72353 (JP, A) JP-A-4-53809 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) C08F 290/00-290/14 C08F 299/00-299/08 C08F 4/00-4/82 C08L 1/00-101/14

Claims (3)

(57) [Claims] When a urethane (meth) acrylate liquid resin comprising a urethane (meth) acrylate and a vinyl monomer copolymerizable with the urethane (meth) acrylate is radically cured, 1) an organic peroxide, 2) An aromatic tertiary amine, 3) a substance capable of forming a covalent valence bond with a lone pair of electrons of the aromatic tertiary amine, and the above three components 1) to 3) coexist. A method for curing a urethane (meth) acrylate liquid resin. 2. Radical curing of a urethane (meth) acrylate liquid resin comprising a urethane (meth) acrylate and a vinyl monomer copolymerizable with the urethane (meth) acrylate, 4) an organic peroxide, 5) A coordination compound based on a covalent valence bond between an aromatic tertiary amine and a substance capable of forming a covalent valence bond with a lone pair of electrons possessed by the aromatic tertiary amine; A method for curing a urethane (meth) acrylate liquid resin, comprising coexisting components. 3. The method for curing a urethane (meth) acrylate liquid resin according to claim 1, wherein the resin transfer molding method or the reaction injection molding method is used.