JP2508135B2 - Visible light curable polyester resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a composition comprising a specific visible light curing agent and a polyester resin, and particularly has a long pot life in a dark place, a high curing rate, and The cured molded article relates to a visible light curable polyester resin composition having a small difference in hardness between the front and the back.

<Prior Art> It is known that a radically polymerizable unsaturated polyester resin can be cured by adding a photocuring agent and irradiating it with ultraviolet rays (UV) or visible rays. For the curing of thin films of resins used as surface coatings and inks, in particular UV-established methods have been established. However, in the case of a thick coating film or glass fiber reinforced resin, UV irradiation is not appropriate because light is absorbed by the resin or glass fiber and the resin cannot be sufficiently cured. It is also known that visible light is effective for photo-curing such a thick coating film or glass fiber reinforced resin.

Various curing systems for unsaturated polyester resins with visible light have been reported. For example, JP-B-60-15646 proposes a combination of a benzoyl oxime carbonate ester derivative and a photoreducible dye as a photocuring agent, for example, eosin and a tertiary amine. On the other hand, in Japanese Patent Publication No. 54-10986, Japanese Patent Publication No. 57-59246 and Japanese Patent Publication No. 60-8241, combinations of α-diketones and tertiary amines are reported. In addition, those using photo-curing agent of acylphosphine oxide are Japanese Patent Publication No. 60.
-8047. On the other hand, a method using a peroxide in combination is also known. For example, JP-B-57-202304 uses benzophenone or benzyl as a photo-curing agent, and t-butylperoxybenzoate, methyl ethyl ketone peroxide, and cyclohexanone peroxide as peroxides.

<Problems to be Solved by the Invention> However, the above-mentioned known methods have the following problems, respectively. A polyester resin composition containing a curing agent in which a derivative of benzoyl oxime carbonate ester, a photo-reducing dye and a tertiary amine is combined has a slow curing rate and a cured molded article has low hardness. In addition, the hardness of the back surface of the cured molded article is low in the case of a polyester resin composition containing a combination of α-diketone and a tertiary amine or acylophosphine oxide as a curing agent.

On the other hand, the polyester resin composition containing a photo-curing agent combined with peroxide has no problem with the hardness of the back surface of the molded product, but has a short pot life of about one week.

As described above, the known visible light curing agent, when mixed with a resin for curing, has a long pot life, and the physical properties of the cured molded product, especially the hardness is large, and the entire surface is almost uniform and Nothing is known that has the characteristic that there is little difference on the back side. In particular, FRP is a major application of polyester resins, but in this case, it is not suitable for practical use because there is a difference in hardness between the front and back of the cured molded product.

It is an object of the present invention to provide a visible light curable polyester resin composition which has a long pot life, and can be cured by photocuring to give a cured molded product having a high hardness and a small difference in hardness between the front and back.

<Means for Solving Problems> The present invention, 100 parts by weight of an unsaturated polyester resin,
A light consisting of a) 0.1-5 parts by weight of α-diketone, b) 0.1-5 parts by weight of benzyl dimethyl ketal, c) 0.1-10 parts by weight of tertiary amine and d) 0.01-5 parts by weight of peroxyketal. A visible light curable polyester resin composition comprising a curing agent.

Next, each component contained in the composition of the present invention will be described.

The unsaturated polyester resin is a normal unsaturated polyester resin, for example, an ethylenically unsaturated dibasic acid such as maleic anhydride or fumaric acid or its anhydride, and glycols such as ethylene glycol or propylene glycol are mainly used. It is produced by dissolving the unsaturated polyester obtained by the esterification reaction as a raw material in a polymerizable vinyl monomer.

 The α-diketone is represented by the following formula.

In the formula, R ₁ and R ₂ represent a hydrocarbon group having 1 to 12 carbon atoms. R ₁ ,
R ₂ may be the same or different. R ₁ and R ₂ may be bonded directly or via a divalent hydrocarbon group. Preferred α-diketones are, for example, benzyl, camphorquinone and the like.

The amount of this α-diketone is 100% of unsaturated polyester resin.
It is in the range of 0.1 to 5 parts by weight, preferably 0.3 to 3 parts by weight, and more preferably 0.5 to 2 parts by weight, based on parts by weight. If it is less than 0.1 part by weight, the hardness of the cured molded article is low because the curing is insufficient even when irradiated with light. If it exceeds 5 parts by weight, quenching begins to occur and it is economically disadvantageous.

Benzyl dimethyl ketal can be used alone or in combination of two or more, and the amount thereof is 100% of unsaturated polyester resin.
0.1 to 5 parts by weight, preferably 0.3
To 3 parts by weight, more preferably 0.5 to 2 parts by weight.
If the amount is less than 0.1 part by weight, the surface of the cured molded article will be less cured and the surface will be sticky. Further, if it exceeds 5 parts by weight, quenching starts to occur and it is economically disadvantageous.

 The tertiary amine is represented by the following formula.

In the formula, R ₃ , R ₄ and R ₅ represent a hydrocarbon group having 1 to 12 carbon atoms. R ₃ , R ₄ and R ₅ may be the same or different. Also R ₃ ,
Two of R ₄ and R ₅ may be cyclized with N. Specific compounds include, for example, trialkylamine, N-alkylmorpholine, N-cycloalkylmorpholine, and the like, and the alkyl group is preferably an ethyl group or a methyl group. The amount of the tertiary amine is 0.1 to 10 parts by weight, preferably 1 to 8 parts by weight, and more preferably 2.5 to 6 parts by weight, based on 100 parts by weight of the unsaturated polyester resin.
If the amount is less than 0.1 part by weight, the resin composition will not cure, and if it exceeds 10 parts by weight, the effect of the tertiary amine on the physical properties of the cured product will be
As in the case of 10 parts by weight, it is economically disadvantageous and the amine tends to remain.

 Peroxyketal is represented by the following formula.

In the formula, R ₆ and R ₇ represent a hydrocarbon group having 1 to 9 carbon atoms. R ₆ ,
R ₇ may be the same or different.

R ₆ and R ₇ may be bonded directly or via a divalent hydrocarbon group. R ₈ and R ₉ represent an alkyl group having 4 to 8 carbon atoms.
R ₈ and R ₉ may be the same or different. R ₈ and R ₉ may be bonded directly or via a divalent hydrocarbon group.

Specific examples include 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane and 1,1-bis (t
-Butylperoxy) cyclohexane, n-butyl 4,4,
Bis (t-butylperoxy) valerate, 1,1-bis (t-butylperoxy) cyclododecane, 3,3,6,6,9,
9-hexamethyl-1,2,4,5-tetraoxocyclononane and the like.

The amount of peroxyketal is based on unsaturated polyester resin.
0.01 to 5 parts by weight per 100 parts by weight, preferably
The amount is 0.025 to 3 parts by weight, more preferably 0.05 to 2 parts by weight. If it is less than 0.01 part by weight, the resin composition is insufficiently cured,
The back surface of the molded product has low hardness. Even if it exceeds 5 parts by weight, the effect is the same as 5 parts by weight, which is economically disadvantageous.

<Effect of the invention> The visible light curable polyester resin composition of the present invention is
Has a long pot life in the dark and has a fast curing rate under visible light irradiation. Further, the degree of curing of the cured molded product is high, and the hardness of the molded product does not vary depending on the location, and the difference in hardness between the front and back is small.

That is, the visible light curable polyester resin composition of the present invention has a long pot life, and the hardness of the cured molded product thereof is high, and the hardness of the entire molded product is small, and the hardness of the surface and the back surface of the molded product is small. It has a characteristic that the difference is small, which was not found in the conventional compositions.

<Example> (Measurement of pot life) Examples 1 to 7 65 parts by weight of an unsaturated polyester having an average molecular weight of 2700 condensed with 1 mol of orthophthalic acid, 1 mol of fumaric acid, and 2 mol of propylene glycol, and 35 parts by weight of styrene monomer. A photocuring agent having a different composition was added to and mixed with 100 g of the unsaturated polyester resin composed of and to obtain a visible light curable polyester resin composition of the present invention. Then each of the above compositions
30 g was packed in a test tube, sealed, and allowed to stand in the dark at 25 ° C., the time until gel formation was measured, and this time was defined as the pot life.

Table 1 shows the composition of the photo-curing agent added to the resin and the pot life in this example.

Comparative Examples 1 to 4 In 100 g of a polyester resin having exactly the same composition as that described in Examples 1 to 7, a curing agent contained in the resin composition of the present invention containing no peroxyketal was compared with Comparative Example 1,
A resin composition was prepared as Comparative Examples 2, 3 and 4 containing no peroxide and containing a peroxide other than peroxyketal, and the resin composition was treated in exactly the same manner as in Examples to measure the pot life. The composition of the curing agent and the pot life are shown in Table 1.

All examples have a pot life of around 3 weeks.
Comparative Example 1 is as long as 31 days, but Comparative Examples 2 to 4 are extremely short.

(Curing Rate, Hardness Measurement of Cured Molded Products) Examples 8 to 12 and Comparative Examples 5 to 10 Measurements by the same resin composition of the present invention as those used in Examples 1, 2, 3, 4, and 5. Examples 8, 9, 10, 11, and 12, the resin composition having the same composition as Comparative Example 1, the resin composition having the same composition as Comparative Example 2, and the resin composition of the present invention of Example 1, Each resin composition except one of the photocuring agents, namely, camphorquinone, N-ethylmorpholine, benzyldimethylketal, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane was removed. The measurement was performed using visible light as Comparative Examples 5, 6, 7, 8, 9, and 10, and the curing rate and the hardness of the cured product were evaluated.

The evaluation method is as follows.
It was placed in a cylindrical container having a height of 1.5 cm and a height of 7 cm (illuminance of about 20,000 lux) just below six 20 W daylight fluorescent lamps and cured. At that time, the maximum exothermic temperature and the curing time (time to reach the maximum exothermic temperature) were determined by inserting a thermocouple into the center of the resin and measuring the curing exothermic curve. Further, on the day after curing, the hardness of the front surface and the back surface of the cured product against irradiation light was measured with a Barcol hardness meter 934- (1). Table 2 shows the results.

As a result, in Comparative Example 5 in which the composition of the present invention lacked peroxyketal, the hardness of the back surface was low. In Comparative Example 6 in which t-butylperoxybenzoate was used instead of peroxyketal, the hardness of the back surface of the cured product was improved and became almost equal to that of the front surface, but as shown in Comparative Example 2, the pot life was extremely high. Short. As shown in Comparative Examples 7 and 8, neither camphorquinone nor N-ethylmorpholine was deficient in curing. Further, as shown in Comparative Examples 9 and 10, when the benzyl dimethyl ketal was lacking, the hardness of the surface was decreased, and when the peroxyketal was lacking, the hardness of the back surface was decreased, resulting in poor curing. On the other hand, when peroxyketal is used together as shown in Examples 8 to 12, the difference in hardness between the front and back is small and the hardness is high. Moreover, the pot life is long as already shown in Examples 1 to 7.

Examples 13 to 18 Examples 13 and 14 in which the amount of camphorquinone was changed, Examples 15 and 18 in which the amount or kind of amine was changed, and those in which the amount of oxyketal was changed in Examples 13 to 18 16 and 17, curing was performed by visible light in exactly the same manner as in Examples 8 to 12, and the curing time, the maximum exothermic temperature and the hardness were measured. The composition of the curing agent in the composition and the measurement result are
Shown in the table. Table 3 shows that there is little difference in hardness between the front and back of the cured product in any of the examples.

(Production of Cured Molded Body ... FRP Plate ... and Its Physical Properties) Example 19, Comparative Examples 11 and 12 FRP plates were prepared from the resin compositions, and the physical properties thereof were measured.

That is, the visible light curable polyester resin composition of the present invention used in Example 1 as a FRP plate raw material (Example 19), the resin composition used in Comparative Example 1 (Comparative Example 11), and the resin used in Comparative Example 2 A composition containing the composition (Comparative Example 12) was used. The weight% of the curing agent in the composition relative to the resin in Table 4
Indicates. 30 g of each of the compositions was impregnated into a stack of three # 450 glass mats, and the impregnated products were laminated. According to the same manner as in Example 8, the laminate was placed 7 cm under the fluorescent lamp and irradiated for 7 minutes. Bending test of each FRP plate to be generated according to the method of JIS-K7203, bending stress at break,
The elastic modulus was calculated.

Separately, with respect to each of the above compositions, a casting plate prepared by setting the irradiation time to 30 minutes (glass fiber is not included)
I got The temperature dispersion curve of dynamic viscoelasticity of this casting plate was measured using Rheolograph Solid (Toyo Seiki),
The crosslink density (ρ) was determined by applying the storage elastic modulus (E ′) in the rubber region to Tobolsky's ideal rubber state equation ρ = dE′RT / 3.

In the formula, d is the resin density, R is the gas constant, and T is the absolute temperature.

Table 4 shows the physical properties such as the composition of the cured product in the composition, the crosslink density of the FRP plate and the casting plate, and the amount of residual styrene.

Table 4 shows that the moldings produced from the composition of the present invention are FR
It is shown that both P and casting plates have excellent physical properties.

Claims (4)

(57) [Claims] 1. 100 parts by weight of unsaturated polyester resin, a) 0.1 to 5 parts by weight of α-diketone, b) 0.1 to 5 parts by weight of benzyl dimethyl ketal, and c) 0.1 to 10 parts by weight of tertiary amine. And d) a visible light curable polyester resin composition containing 0.01 to 5 parts by weight of a photocuring agent comprising a peroxyketal. 2. The visible light curable polyester resin composition according to claim 1, wherein the α-diketone is benzyl or camphorquinone. 3. The visible light curable polyester resin composition according to claim 1, wherein the tertiary amine is N-ethylmorpholine or trialkylamine. 4. A peroxyketal is 1,1-bis (t-
Butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, n-butyl 4,4'-bis (t-butylperoxy)
Valerate, 1,1-bis (t-butylperoxy) cyclododecane and 3,3,6,6,9,9-hexamethyl-1,2,4,5
-The visible light curable polyester resin composition according to claim 1, which is one kind or two or more kinds selected from the group consisting of tetraoxocyclononane.