JP2840120B2 - Curable resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to wood, metal, FRP (Fiber Reinforced Plas).
tics), quickly cures at the mutual bonding interface of various substrates to give excellent peel strength and excellent water resistance,
An object of the present invention is to provide a curable resin composition having a high practical value as an adhesive.

[Conventional technology]

Conventionally, when an unsaturated polyester resin is used as an adhesive to bond wood, metal, FRP, and the like to each other, there has been a disadvantage that peeling from the bonding surface is easily caused by an external force.

Generally, the mechanical behavior applied to the bonding surface depends on complex factors such as shearing force, torsion, impact, bending moment, etc. In this regard, especially when unsaturated polyester resin is used as the adhesive, the shear strength at the bonding interface is certainly Is large, but it is known that the peel strength is weak, and it can be easily understood that when the above-described composite force is applied to the bonding interface, the peel is easily performed.

Therefore, as described above, when an unsaturated polyester resin is used as an adhesive for bonding various base materials, additional bonding means such as bolt and nut tightening may be used due to the above-mentioned weakness in practical use. There is a practical disadvantage that causes a reduction in work efficiency and an increase in cost due to the necessity of using a combination of means.

The inventors of the present invention have conducted intensive studies on matters necessary to improve the peel strength, which is a disadvantage of the unsaturated polyester resin cured product as described above, and found that the cured product has a tensile strength and a tensile strength. It has been found that the modulus of elasticity has a very large effect on the peel strength, that is, the higher the tensile strength and the lower the tensile modulus, the greater the peel strength.

Such a relationship is a completely contradictory phenomenon in a conventionally used unsaturated polyester resin cured product, that is, it is general that the tensile strength decreases as the tensile elastic modulus decreases. This is apparent from the experiments of the present inventors shown in FIG.

In other words, the present inventors have made the unsaturated polyester resin having a low degree of unsaturation obtained by reducing the molar ratio of the unsaturated acid to the saturated acid for the purpose of lowering the tensile modulus or by using a long-chain saturated acid and a long-chain glycol. The performance of the unsaturated polyester resin as an adhesive was evaluated for the unsaturated polyester resin.In this case, when the tensile modulus of the cured product of the resin decreases to 1/5 to 1/10, the tensile strength also increases to 1/30 to The peel strength was reduced to 1/50, and a sufficient peel strength as an adhesive could not be obtained.

[Problems to be solved by the invention]

An object of the present invention is to provide a curable resin composition having a very useful value as an adhesive having a high peel strength to a substrate and excellent in water resistance.

[Means for solving the problem]

As a result of further studies based on the above facts, the present inventors have improved tensile strength by providing a new bonding mode in an unsaturated polyester resin having a low tensile modulus, that is, a low unsaturated degree. The present inventors have found that a curable resin composition having a very useful value as an adhesive having a high peel strength to a substrate after curing as a result and having excellent water resistance as a result has led to the achievement of the present invention. Things.

That is, the present invention relates to (A) 10-terminal hydroxyl groups in a polymerizable α, β-ethylenically unsaturated polyester having a molecular weight per double bond titer of 700 to 3000 in the molecule.
A product obtained by reacting not less than 2% by weight of a 2,5 (6) -diisocyanatomethyl-bicyclo [2,2,1] heptane compound; (B) CH ₂ CHC polymerizable with the product; <A curable resin composition comprising a group-containing monomer.

The α, β ethylenically unsaturated polyester used in the present invention needs to have a molecular weight per double bond titer of 700 to 3000, but when the molecular weight per double bond titer is less than 700, When the obtained curable resin composition is used as an adhesive for bonding a substrate as described below, it cannot show sufficient peel strength, and when the molecular weight exceeds 3,000, the obtained cured When the conductive resin composition is used as an adhesive for bonding a substrate as described below, not only is not sufficient peel strength obtained, but also the water resistance is reduced.

Thus, in the present invention, the unsaturated polyester and 2,2
5 (6) -diisocyanatomethyl-bicyclo [2,2,1]
In the reaction with the heptane compound, it is important to react 10% by weight or more of the hydroxyl group of the unsaturated polyester with the diisocyanate compound,
When the diisocyanate-based compound is reacted with less than 10% by weight of the hydroxyl groups of the unsaturated polyester, the resulting curable resin composition is used as an adhesive to bond a substrate as described below. When used, there is a disadvantage that sufficient peel strength cannot be obtained, which is not suitable for the present invention.

The α, β ethylenically unsaturated polyester in the present invention is produced by dehydration condensation of an organic acid and a polyhydric alcohol as shown below.

As the organic acid, maleic acid, fumaric acid, anhydrides of these acids, citraconic acid, unsaturated dibasic acids such as chloromaleic acid alone or further phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, adipic acid And at least one of saturated monobasic acids such as octenoic acid and benzoic acid, and saturated tribasic acids such as trimellitic acid and citric acid. Glycols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, hexanediol, and bisphenol A propylene oxide adducts are generally used, and trihydric alcohols such as glycerin and trimethylolpropane are added to these glycols. You may use together.

The acid value of the α, β ethylenically unsaturated polyester obtained by the dehydration condensation reaction of the unsaturated acid, the organic acid of the saturated acid and the polyhydric alcohol indicates the concentration of the terminal acid group in the unsaturated polyester. In the present invention, mg of caustic potassium required for neutralization per 1 g of unsaturated polyester
The number is usually 40 or less, preferably 15 or less, and the terminal hydroxyl value in the unsaturated polyester used in the present invention indicates the concentration of the terminal hydroxyl group in the unsaturated polyester, and the equivalent amount of acid is used. In the present invention, it is preferable that the number of mg of caustic potash required for summing is represented by a value converted to 1 g of unsaturated polyester and is larger than the acid value. The hydroxyl value can be determined by a conventionally known acetylation method in which acetic anhydride is added to the unsaturated polyester, the terminal hydroxyl groups thereof are acetylated, and excess acetic anhydride is back titrated with potassium hydroxide.

From the terminal hydroxyl value of the unsaturated polyester thus obtained, the amount of terminal hydroxyl groups of the unsaturated polyester is known, and 10% by weight or more of this amount is 2,5 (6) -diisocyanate required for the reaction. By adding a methyl-bicyclo [2,2,1] heptane-based compound to react the terminal hydroxyl group of the unsaturated polyester with the diisocyanate compound, the product (A) described in the present invention can be obtained. Can be obtained.

In the present invention, as described above, 10% by weight of the terminal hydroxyl groups in the α, β ethylenically unsaturated polyester using the 2,5 (6) -diisocyanatomethyl-bicyclo [2,2,1] heptane compound. In this case, the terminal hydroxyl group is preferably reacted at a level of 100% by weight or less.

The diisocyanate compounds obtained by reacting 2,5 (6) -diisocyanatomethyl-bicyclo [2,2,1] heptane with the following glycols used in the present invention are used. Examples thereof include diethylene glycol, triethylene glycol, 1,4-butylene glycol, 1,6 hexanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol and the like.

Also, 2,5 (6) -diisocyanatomethyl-bicyclo [2,2,1] heptane is, for example, 2,5 (6) -diaminomethyl-bicyclo [2,2,1] heptane obtained by isoamyl acetate and O- In a mixed solvent of dichlorobenzene, hydrogen chloride gas is blown to cause a salt formation reaction, then phosgene is blown to cause a phosgenation reaction, and then rectification is performed.

Next, as the monomer of the above-mentioned (B) used in the present invention, that is, the monomer having a CH ₂ ＣC <group copolymerizable with the above-mentioned product of the above (A), for example, styrene, chlorostyrene ,
Examples include vinyl toluene, methyl methyl methacrylate, acrylic acid, methyl methacrylic acid, and the like.

The ratio of (A) and (B) described above used in the present invention is:
Usually, (A) is 30% by weight based on the total amount (weight) of the two.
8080% by weight, preferably 40% -70% by weight.

As a method of curing the curable resin composition of the present invention,
All curing agents conventionally used for curing unsaturated polyester resins can be used.For example, when curing at room temperature, a combination of methyl ethyl ketone peroxide and cobalt naphthenate, a combination of benzoyl peroxide and dimethylaniline, etc. In the case of curing at a high temperature, benzoyl peroxide, tert-butyl peroctoate, tert-butyl perbenzoate, etc. may be used alone or in combination.

When the curable resin composition of the present invention is used as an adhesive, the composition contains, as a viscosity modifier, a conventionally known filler such as calcium carbonate, talc, and asbestos, other pigments, a thixotropic agent, and the like. Addition and mixing may be used.

Since the curable resin composition of the present invention has excellent peel strength against adhesion of a substrate and good water resistance, for example, an adhesive assembly of a vertically divided FRP purification tank, a mechanically molded FRP
For water treatment such as production of water tanks by combined bonding of panels
It is especially useful as an adhesive for bonding and assembling FRP products.
There is also practical value in the adhesion of wood and aluminum plate when making disaster prevention protection and makeup of wood with aluminum plate,
In addition, the industrial value is very large, such as adhesion of various substrates other than FRP, for example, adhesion to the same or different substrates in metals, wood, glass, ceramics and the like.

〔Example〕

Examples are shown below. The parts and percentages shown in the examples are weight values, and the peeling test and the water resistance test were carried out by the following methods.

Peeling test was performed using two FRP molded products that are 1 inch wide and 3 mm thick and bent at right angles. After applying the curable resin composition obtained in each of Examples and Reference Examples to be described later to the interface between the two molded articles so that the two-shaped FRP molded articles are bonded together to form the curable resin composition. Obtained by curing the object So that the peeling force acts on the adhesive surface of Were fixed to the upper and lower chucks of a tensile tester by Instron, and pulled up and down at a speed of 5 mm / min, and the peel strength was measured by the tensile load at the time of breaking.

Next, a water resistance test was obtained in the same manner as in the case of the above-mentioned peel test. After immersion in boiling water at 100 ° C for 100 hours, The peel strength was measured in the same manner as the test was performed, and this measured value was separately measured before immersion. The ratio (percentage) to the measured value of the peel strength is shown in the following table.

In addition, 2,5 (6) -diisocyanatomethyl-bicyclo [2,2,1] heptane (BCHI) was produced according to the following Reference Example.

Reference Example As a solvent, 678 g of isoamyl acetate and 2189 g of O-dichlorobenzene were mixed to prepare a solvent for salt formation and phosgenation (hereinafter, referred to as a mixed solvent), and 1126 g of the mixed solvent was put into a three-necked three-necked flask and stirred. While cooling with ice water to 5 ° C. Hydrogen chloride gas was blown into this at a rate of 1.6 Nl / min for 30 minutes, and then about 60% of the 2,5-isomer and about 2,6-isomer
A 40% mixture of diaminomethyl-bicyclo [2,2,
1] Heptane (BHCA) 250.0 g (1.62 mol) mixed solvent 1750
The solution (concentration: 12.5% by weight) dissolved in g was dropped into the liquid in the flask over 2 hours. Continue cooling during the dropping, keep the temperature inside the flask at 10 to 15 ° C, and blow hydrogen chloride gas at 1N.
Continued at l / min.

After completion of the dropwise addition of the starting diamine solution, blowing of hydrogen chloride gas was continued at a rate of 0.4 Nl / min for 2 hours while maintaining the temperature inside the flask at 25 ° C. or lower, to complete the salt formation reaction. In the salt-forming reaction, agglomeration of hydrochloride particles did not occur, and the transition was extremely smooth, and a slurry of white uniform fine particles was obtained.

After completion of the salt-forming reaction, the temperature inside the flask is increased from 25 ° C to 160 ° C
The phosgene reaction was started by gradually blowing phosgene from 100 ° C. while the temperature was raised in 0 minutes. Blowing of phosgene was continued at a rate of 100 g / h to 120 g / h while adjusting the internal temperature to 160 ± 1 ° C. with a mantle heater. After about 6 hours from the start of phosgene blowing, the property of the reaction solution changed from a slurry (white) to clear (red), and then phosgene gas was blown at a rate of 50 g / h for 30 minutes, and the phosgenation reaction was terminated. did.

Thereafter, into the flask the reaction solution, subjected to 80 minutes blown degassed with N ₂ gas at a rate of 1.3Nl / min, while this liquid temperature is 160
± 1 ° C. After cooling and filtration, the filtrate was desolvated and then rectified under vacuum to obtain a main fraction of 110-116 ° C / 0.4-0.6 torr.
06.5 g was obtained.

The main fraction obtained from the results of elemental analysis, IR spectrum, NMR spectrum and the like was confirmed to be the target product.

Examples 1 to 5 and Comparative Examples 1 to 3 Regarding unsaturated acids, saturated acids and glycols, the types and the use ratios shown in Table 1 were charged into a reactor in a nitrogen gas stream at a temperature of 210 to 220 ° C. The reaction was continued until the acid value reached 10. The hydroxyl value and the molecular weight per double bond titer of the unsaturated polyester obtained are shown in Table 1.

Take 600 g of each of the above unsaturated polyesters, dissolve in 400 g of xylene, add the respective type and amount of the diisocyanate compound shown in Table 1 and add the terminal hydroxyl groups of the unsaturated polyester at 70 ° C. for 5 hours. After the reaction, xylene was removed under vacuum, and then styrene was added so as to have a content shown in Table 1 to obtain a curable resin composition.

In addition, 2,5 shown as a diisocyanate compound
(6) -diisocyanatomethyl-bicyclo [2,2,1]
Heptane (BCHI) or tolylene diisocyanate (TD
I) was directly added to a solution of the unsaturated polyester in xylene. Similarly, a diisocyanate compound obtained by reacting polypropylene glycol (PPG) shown as a diisocyanate compound with BCHI or TDI is prepared by dissolving 1 mol of PPG in xylene and adding 2 mol of BCHI or TDI.
It was obtained by reacting at 5 ° C. for 5 hours, and the amount necessary for reacting with the terminal hydroxyl groups of the unsaturated polyester was added to a solution of the unsaturated polyester in xylene.

The curable resin composition obtained in each of the above was added with 1% of methyl ethyl ketone peroxide based on the composition.
Add a styrene solution containing 0.5% cobalt naphthenate 6% and use it to form a shaped FRP as described above. Then, the peel strength was measured and a water resistance test was performed according to the methods described above, and the results are also shown in Table 1.

[Effects of the Invention] The curable resin composition of the present invention has a urethane skeleton in the resin, and the adhesive strength increases with the polymerization of the ester, the tensile strength, the elongation improves, and as an adhesive such as FRP. Useful.

Continuation of the front page (51) Int.Cl. ⁶ Identification symbol FI C09J 167/06 C09J 167/06 175/14 175/14 (56) References JP-A-3-290420 (JP, A) JP-A-4- 33969 (JP, A) JP-A-4-226965 (JP, A) JP-A-4-91113 (JP, A) US Patent 3,595,917 (US, A) US Patent 3,492,330 (US, A) US Patent 3,646,132 (US, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08F 299/00-299/08 C08F 283/00-283/14 C09J 101/00-201/10 C08G 18/00-18/87

Claims (1)

(57) [Claims] (A) 10% by weight of terminal hydroxyl groups in a polymerizable α, β ethylenically unsaturated polyester having a molecular weight per double bond titer of 700 to 3000 in the molecule.
The above is a product obtained by reacting with a 2,5 (6) -diisocyanatomethyl-bicyclo [2,2,1] heptane-based compound; and (B) a CH ₂ ＣC <group capable of polymerizing with the product. A curable resin composition comprising: a monomer having the formula: