JPH04335017A - Thermosetting resin composition - Google Patents

Abstract

PURPOSE:To prepare the title compsn. which is stable and easy to handle and gives a cured article excellent in resistance to heat and impact by compounding a polyisocyanate compd., a polyol compd., and a polyepoxy compd. in a specified ratio and using a specific catalyst. CONSTITUTION:The title compsn. is prepd. by compounding a polyisocyanate compd. a polyol compd., and a polyepoxy compd. in such a ratio that the amts. of hydroxyl groups of the polyol compd., epoxy groups of the polyepoxy compd., and the sum of the hydroxyl groups and the epoxy groups, each based on 100 equivalents of isocyanate groups of the polyisocyanate compd., are 10-40, 5-20, and 15-45 equivalents, respectively. The catalyst used is a mixture of a quaternary ammonium salt of the formula (wherein R1, R2, R3, and R4 are each independently a 1-20C aliph., alicyclic, or arom. hydrocarbon group provided that the sum of the number of carbon atoms contained in R1, R2, R3, and R4 is at least 12; and X is halogen) with a tin compd.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new thermosetting resin composition which provides molded articles with excellent heat resistance, is stable and has good handling properties. More specifically, it provides a cured resin molded product with excellent heat resistance, chemical resistance, machinability, and mechanical properties (especially impact resistance), and also has storage stability and
The present invention relates to a thermosetting resin composition with excellent curing controllability.

0002

BACKGROUND OF THE INVENTION In recent years, with the advancement of technology, there has been a demand for resins with excellent heat resistance, mechanical properties, and moldability. Among these resins, particularly reactive molding type resins using reactive monomers or oligomers, that is, resins in which molding and polymerization are performed simultaneously using raw materials with relatively low viscosity (preferably liquid at room temperature) are attracting attention. ing. Known examples of such resins include polyurethane resins, epoxy resins, unsaturated polyester resins, and vinyl ester resins, some of which have been commercialized.

However, each of these resins has its advantages and disadvantages; for example, polyester resin has low heat resistance;
Although unsaturated polyester resins and epoxy resins have better heat resistance than polyurethane resins, they have the problem of being hard and brittle.

[0004] As a method for improving the heat resistance of polyurethane resins, the introduction of isocyanurate rings by trimerization of isocyanates has been known for a long time, for example, from Japanese Patent Publication No. 44-16669, and has been put to practical use. However, even with improved heat resistance, the improvement is only 20 to 30 degrees Celsius over the current one, and the heat distortion temperature is only 150 to 16 degrees Celsius at most.
It stays at 0℃.

[0005] Thermosetting resins using polyisocyanate as one raw material have long been known to utilize oxazolidone ring formation, which is a ring-forming reaction between an isocyanate group and an epoxy group. A combination of an isocyanurate ring obtained by trimerizing isocyanate and this oxazolidone ring formation as described in JP-A-62-62879 has also been proposed.

Although this material has high heat resistance, it is brittle and has low impact resistance. Such brittleness and low impact resistance are common characteristics of thermosetting resins. As an improvement,
Generally, an elastic material such as rubber is added, but
The improvement effect is not significant, and when the amount of the elastic material added is increased, other properties such as a significant decrease in heat deformation temperature are brought about.

[0007] Therefore, the present inventors first developed a composition of a thermosetting resin having excellent heat resistance and good impact resistance, which is composed of a polyisocyanate compound, a polyol compound, a polyepoxy compound, and a curing catalyst. proposed a composition (Japanese Patent Application No. 2-199202), this composition was
Generally, the reactivity is high, and the polymerization reaction progresses easily even at room temperature.
Increased viscosity, gelation, or the formation of insoluble substances occur, leading to problems with the stability of the liquid and the reproducibility of the properties of molded products. Such problems are particularly likely to occur when a tertiary amine is used as a curing catalyst.

Tetramethylammonium iodide is already known as an oxazolidone-forming catalyst other than tertiary amines. (Journal of A
pplied Polymer Science,
1994, Vol. 9, 1965) The present inventors investigated a system containing such a quaternary ammonium salt and found that although the stability of the composition increased, the improvement in the properties of molded products was small, especially in terms of thermal deformation. It was found that it was difficult to obtain a product with a high temperature.

Therefore, the present inventors added a tin-based catalyst known as a urethane-forming catalyst to such a composition, and when used within a specific amount range, the stability of the liquid increased and It was discovered that the resulting molded product has excellent properties, and the present invention was achieved.

0010

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a composition comprising a polyisocyanate compound, a polyol compound, a polyepoxy compound, and a curing catalyst that has excellent heat resistance and impact resistance and is stable. sex,
An object of the present invention is to provide a thermosetting resin composition that is easy to handle.

[0011]

[Means for Solving the Problems] The object of the present invention as described above is to provide a thermosetting resin composition mainly consisting of a polyisocyanate compound (A), a polyol compound (B), a polyepoxy compound (C), and a curing catalyst. ,(A)(
B) (C) Each component contains 10 to 40 equivalents of hydroxyl groups in the polyol compound (B), and 10 to 40 equivalents of hydroxyl groups in the polyepoxy compound (C) per 100 equivalents of isocyanate groups in the polyisocyanate compound (A). 5 to 20 equivalents, and the sum of the hydroxyl group and the epoxy group is 15 to 20.
A quaternary ammonium salt containing 45 equivalents and having a curing catalyst represented by the following formula (1)

[Chemical formula 2] (However, in the above formula (1), R1 to R4 are the same or different, and each is an aliphatic, alicyclic or aromatic hydrocarbon having 1 to 20 carbon atoms, and R1 to R4 are The total number of carbon atoms contained in the shown substituents is 12 or more. Also, X represents a halogen.
This is achieved by a novel thermosetting resin composition containing the above quaternary ammonium salt in a proportion of 0.3 to 3 parts by weight and the tin-based compound in a proportion of 0.001 to 0.25 parts by weight. .

The polyisocyanate compound (A) used in the present invention has at least two isocyanate groups in its molecule, and aliphatic, alicyclic or aromatic polyisocyanates are used.

Examples of aliphatic polyisocyanates include hexamethylene diisocyanate, 2,2,4- or 2,4,4-trimethylene diisocyanate, 1,
Examples of alicyclic polyisocyanates include isophorone diisocyanate, 4,
Examples of aromatic isocyanates include 4'-dicyclohexylmethane diisocyanate, hydrogenated meta- or para-xylylene diisocyanate, and examples of aromatic isocyanates include 2,4- or 2,6-tolylene diisocyanate,
, 4'-diphenylmethane diisocyanate, 3,4'
Alternatively, 4,4'-diphenyl ether diisocyanate, meta- or para-xylylene diisocyanate, etc. can be mentioned.

[0014] Furthermore, polyphenylene polymethylene polyisocyanate produced by isocyanating a polyamine obtained by condensation of aniline and formalin with phosgene, or carbodiimide-modified or polyol-modified polyisocyanates can also be used. Furthermore, isocyanurate ring-containing polyisocyanates obtained by trimerizing polyisocyanates, such as trimers of tolylene diisocyanate, etc. can also be used.

[0015] These can be used alone or in a mixture of two or more. Among these, carbodiimide, polyol-modified 4,4'-diphenylmethane diisocyanate, polyphenylenepolymethylene polyisocyanate, etc., which are liquid and have low viscosity at room temperature, are preferably used.

Polyol compound (B) used in the present invention
) has at least two hydroxy groups in its molecule.

As such polyol compound (B),
Polyether polyols, such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc., or polyester polyols, such as adipate polyol, polycaprolactone polyol, polycarbonate polyol, etc., or polyether polyester polyol, polyester amide polyol, etc. Polymer polyols having a certain degree of repeating units, ethylene glycol, propylene glycol, 1,3-butanediol, dipropylene glycol, 1,4- or 1,5-hexanediol, glycerin, pentaerythritol, etc., cyclohexanediol, Examples include cyclohexanedimethanol, bisphenol A, or its ethylene oxide or propylene oxide adduct. Alternatively, polybutane diene, polybutane diene-styrene copolymer, and polybutane diene-acrylonitrile copolymer having a terminal hydroxyl group may also be used.

These polyol compounds (B) can be used alone or in the form of a mixture, but in order to balance the properties of heat resistance and impact resistance, it is preferable to use a mixture of two or more. It is possible to use a mixture of two types of polyol compounds having different values.

Among such polyol compounds (B),
From the point of view of impact resistance, it is preferable to use a polyol that has been polymerized to some extent, and from the point of view of heat resistance and water resistance, it is preferable to use a polyether polyol mainly in the form of a polyether polyol with the same type of polyol or other polyol compound having a different molecular weight added thereto. be. From the viewpoint of moldability, those that are liquid or close to liquid at room temperature are preferably used.

Polyepoxy compound (C) in the present invention
has at least two epoxy groups in its molecule, and bisphenol A diglycidyl ether,
Bifunctional epoxy compounds such as bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, resorcinol diglycidyl ether, hexahydrobisphenol A diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, phthalate diglycidyl ether, Examples include tri- or higher functional epoxy compounds such as triglycidyl isocyanurate and cresol novolak polyglycidyl ether.

Among these polyepoxy compounds (C), bisphenol A diglycidyl ether and bisphenol F diglycidyl ether, which can be liquid and have a low viscosity at room temperature, are preferably used. Cresol novolac polyglycidyl ether is preferably used to improve heat resistance. Such a polyepoxy compound (C) is preferably liquid or nearly liquid at room temperature.

[0022] In the composition of the present invention, the above (A) (B)
) (C) Each component has 10 to 40 equivalents of hydroxyl groups in the polyol compound (B) and 5 equivalents of epoxy groups in the polyepoxy compound (C) per 100 equivalents of isocyanate groups in the polyisocyanate compound (A). It is contained in a ratio of ~20 equivalents and the sum of the hydroxyl group and the epoxy group is 15 to 45 equivalents.

The reaction between the polyisocyanate compound (A) and the polyol compound (B) produces polyurethane. A larger amount of polyurethane is preferable from the viewpoint of improving the impact resistance of the cured resin, but if the amount is too large, the heat resistance decreases. Therefore, from the viewpoint of the balance between heat resistance and impact resistance of the cured resin, in the present invention, for 100 equivalents of isocyanate groups,
The amount of hydroxyl group is 10 to 40 equivalents, preferably 15 to 30 equivalents. If the amount of hydroxyl groups is less than 10 equivalents, the resulting cured resin will have low impact resistance and will be prone to foaming during reaction (molding). On the other hand, if the amount exceeds 40 equivalents, the heat resistance of the cured resin will decrease.

The epoxy group in the polyepoxy compound (C) reacts with the polyisocyanate to form an oxazolidone ring. This oxazolidone ring is a ring with high heat resistance, and since the epoxy group and the isocyanate group react in a linear structure rather than a network structure, this oxazolidone ring formation is highly resistant from the viewpoint of the heat resistance of the cured resin. Although preferred from the viewpoint of impact resistance, it requires a higher reaction temperature than polyurethane formation or isocyanurate ring formation by trimerization of isocyanate, and therefore lags behind polyurethane formation and isocyanurate ring formation during curing. Therefore, when the number of epoxy groups is increased, the number of unreacted epoxy groups increases, so that the heat resistance, particularly the heat distortion temperature, of the cured resin does not increase.

As a result of studies by the present inventors, the amount of epoxy groups in the curable resin composition is preferably 5 to 20 equivalents, particularly preferably 7 to 18 equivalents, per 100 equivalents of polyisocyanate groups. It turned out that.

[0026] The sum of all hydroxyl groups and epoxy groups in the composition must be 45 equivalents or less. When this sum exceeds 45 equivalents, the rate of trimerization of isocyanate groups decreases, resulting in a decrease in the heat resistance of the cured resin. Particularly preferred is 35 equivalents or less. On the other hand, the minimum sum of hydroxy groups and epoxy groups is 15 equivalents, and if it is less than that, the crosslinked structure due to trimerization of isocyanate will increase, and the heat resistance of the cured resin will increase, but it will become brittle.

The curing catalyst used in the present invention has the following formula (
This is a mixed catalyst of a quaternary ammonium salt represented by 1) and a tin-based compound.

[0028]

[Image Omitted] R1 to R4 and X in the above formula (1) are as described above, but specific examples of R1 to R4 are as follows:
Examples include methyl, ethyl, propyl, butyl, decyl, tetradecyl, benzyl, cyclohexyl, phenyl, and the like. It is preferable that R1 to R4 are all the same, but
It is not necessarily essential that these be the same.

[0029] If the total number of carbons contained in the substituents represented by R1 to R4 is less than 12, the solubility will be poor and the system will become non-uniform, so the total number of carbons must be 12 or more. In addition, as the halogen of X, iodine,
Although bromine, chlorine, and fluorine are available, it is preferable that X be bromine or chlorine in order to perform the curing reaction at an appropriate speed, neither too fast nor too slow.

Specific examples of such quaternary ammonium salts include tetra-n-butylammonium bromide, tetra-n-butylammonium chloride, n-tetradecyltrimethylammonium chloride, and benzalkonium chloride. Among these, when the thermosetting composition of the present invention is used for RTM or S-RIM, a certain amount of time is required for curing. 4-5
For example, tetra-n-butylammonium bromide is suitable.

[0031] Examples of the tin-based compound used in combination with the above-mentioned quaternary ammonium salt include inorganic and organic tin compounds. Examples of inorganic tin compounds include stannous chloride and stannic chloride; examples of organic tin compounds include di-n-butyltin dilaurate, di-n-butyltin diacetate, tri-butyltin acetate, and tetra-n-butyltin. be able to. Among these,
N-butyltin dilaurate, di-n-butyltin diacetate, etc. are easy to handle and are preferably used. The amount of catalyst is determined by the amount of quaternary ammonium salt added to the total amount of resin (i.e., polyisocyanate compound (A) and polyol compound (A)).
0.3 to 3 parts by weight, preferably 0.35 to 1 part by weight, based on 100 parts by weight of the total amount of B) and the polyepoxy compound (C)
Parts by weight. If the amount of catalyst is large, the curing reaction will be too fast and foaming will occur easily. The amount of the tin-based compound is 0.001 to 0.25 parts by weight, preferably 0.0 parts by weight, based on 100 parts by weight of the total amount.
05 to 0.2 parts by weight.

Addition of a tin compound to the catalyst system increases the heat distortion temperature (H.D.T.) of the resulting cured resin and also improves its toughness. However, if this amount is too large, the curing will be too rapid and the heat distortion temperature of the cured resin will also decrease.

[0033] A method for thermosetting the thermosetting resin composition of the present invention to form a molded article is to use a liquid A containing mainly a polyisocyanate compound and a liquid B containing mainly a polyol compound, a polyepoxy compound, and a curing catalyst. Prepare separately and
These two types of liquids are mixed using a mixing head or the like immediately before or during molding to prepare the thermosetting composition of the present invention, and then poured into a mold of a predetermined shape that is preheated as necessary to react. A method of curing is preferably used. However, the components (A), (B), and (C) and the above catalyst may be mixed all at once to prepare the composition of the present invention, and this may be immediately subjected to molding.

The above-mentioned components in the composition of the present invention are reacted and cured in a mold or on a support to form a cured resin. The reaction temperature at this time varies depending on the type of polyisocyanate compound (A), polyol compound (B), polyepoxy compound (C) used, the type of catalyst, the ratio of use thereof, etc., but in order to sufficiently carry out ring-forming polymerization, at least 1
It is necessary to pass through 50°C once.

[0035] Here, passing once means 1 time during molding with a mold.
This includes a method in which the temperature is raised to 50° C. or higher, and a method in which the mold is molded at 150° C. or lower in a mold, and then taken out from the mold and heated to 150° C. or higher. Alternatively, a so-called post-cure method may be used in which the temperature is increased to 150° C. or higher.

[0036] In order to prevent defects such as bubbles from occurring in the molded product, it is preferable to use the latter method, in which molding is performed at a low temperature at first, followed by post-curing.

The upper limit of the reaction temperature is 280°C, preferably 280°C.
The temperature is 40°C, particularly preferably 200°C.

[0038] The reaction time may be any time that is sufficient to fully cure the desired resin. This time varies depending on the type of raw materials used, the proportion used, the reaction temperature, etc., but is preferably 1 minute to 24 hours, more preferably 5 minutes to 10 hours.
The time is particularly preferably about 5 minutes to 10 hours, particularly preferably about 10 minutes to 6 hours.

The thermosetting resin composition of the present invention may optionally contain thermoplastic polymer fibers, fibrous reinforcing materials such as carbon fibers and glass fibers, various fillers, fillers, pigments, coloring agents, and oxidation stabilizers. It can contain agents, ultraviolet absorbers, mold release agents, etc. For example, in the case of a fibrous reinforcing material, the above-mentioned fibrous reinforcing material is inserted into a reaction mold in advance in the form of a fabric, mat, etc. as necessary, and the thermosetting resin composition of the present invention is applied thereon. be able to. In such a case, the heating reaction of each component in the present invention is carried out, for example, in the presence of a fibrous reinforcing material, and it goes without saying that the curable resin containing these reinforcing materials can be obtained as a composite material. Nor.

[0040]

Effects of the Invention According to the present invention, a stable thermosetting resin composition which is liquid at room temperature is provided, and this can be used to improve heat resistance, chemical resistance and mechanical properties, especially impact resistance. Excellent cured resin molded products can be efficiently produced with good reproducibility.

A thick cured resin molded article can be easily obtained from the composition of the present invention. For example, the molding thickness is 20cm
It is also possible to mold objects with a thickness greater than that, and in this case, the center of the molded object will not change color due to heat generation.

Furthermore, the cured resin molded product obtained from the composition of the present invention has good cutting workability, and can be processed into square or circular shapes using an ordinary metal cutting machine, and the inside of the molded product can be cut easily. It can also be easily hollowed out.

[0043]

[Examples] The present invention will be described in detail with reference to Examples. However, the Examples are for illustrative purposes only, and the present invention is not limited thereto. Parts by weight are shown in the middle part of the examples.

[0044]

[Example 1] Carbodiimide-modified 4,4'-diphenylmethane diisocyanate (isocyanate equivalent: 6.90
x 10-3 equivalent/g) (liquid A) was prepared.

Separately, a mixed polyether polyol (OH equivalent, 3.15×10-3 equivalent/g) was prepared by mixing two types of polyether polyols with different molecular weights.
100 parts, polyepoxy compound ("Epicoat 828"
A mixed solution (B
liquid) was prepared.

[0046] These A and B solutions were supplied to an RTM machine in the amount of 200 parts of A solution and 121 parts of B solution, rapidly mixed in the mixing head, and poured into a mold at 140°C. Heat in the mold for 30 minutes, then remove from the mold, 1
After post-curing at 80℃ for 5 hours, a reddish-brown transparent 3
A molded plate with a thickness of mm was obtained. The bending properties, heat distortion temperature (H.D.T.) and notched Izod impact strength (N.I.) of this molded plate are shown in Table 1 below.

When these solutions A and B were stored separately at room temperature for 60 days, the viscosity of each solution was 45%.
cps (30°C) and 365cps (30°C),
There was no change at all, and the properties of the molded plate obtained by molding under the same molding conditions after 60 days were no different from the original one.

[0048]

Comparative Example 1 A composition was prepared in the same manner as in Example 1, except that dibutyltin dilaurate was not used, and a molded article was obtained in the same manner. Its properties (H.D.T. and N.I.) are shown in Table 1.

[0049]

Comparative Example 2 A composition was prepared in the same manner as in Example 1, except that the amount of dibutyltin dilaurate was changed to 1.0 part, and a molded article was obtained in the same manner. Its characteristics are shown in Table 1.

[0050]

[Table 1]

[0051]

[Example 2] Using the A and B liquids of Example 1, the A and B liquids were supplied and mixed using an RTM machine so that the A liquid was 200 parts and the B liquid was 121 parts. The mixture was poured into a cylinder (placed on an aluminum plate and the bottom sealed with adhesive) to a height of about 30 cm.

When left at room temperature, heat was generated and curing started after about 15 minutes. Although it hardened in about 1 hour, the temperature on the outside of the aluminum cylinder was a maximum of 92°C. The product was placed in a hot air dryer as it was and left at 140°C for 1 hour, then raised to 180°C for 5 hours.

Thereafter, it was cooled to room temperature and taken out from the aluminum cylinder to obtain a reddish-brown transparent block-shaped hardened molded product with a diameter of 20 cm and a height of 30 cm. The center of the molded product did not turn black and was uniform, and no foaming was observed.

When I tried to cut the outside of this block-shaped hardened molded product to a diameter of 19.5 cm using a metal cutting machine, it was easily cut, and the center part had an inner diameter of 15 cm and a length of 10 cm.
When I hollowed it out to a cm length, it didn't break and was easy to cut. The finish was good and clean.

Claims (3)

[Claims] Claim 1: A thermosetting resin composition mainly comprising a polyisocyanate compound (A), a polyol compound (B), a polyepoxy compound (C), and a curing catalyst,
The above compounds (A), (B), and (C) are added to 100 equivalents of isocyanate groups in the polyisocyanate compound (A),
The number of hydroxyl groups in the polyol compound (B) is 10 to 4
0 equivalent, the epoxy group in the polyepoxy compound (C) is 5
~20 equivalents, and the curing catalyst is contained in a ratio such that the sum of the hydroxyl group and the epoxy group is 15 to 45 equivalents, and the curing catalyst is
A quaternary ammonium salt represented by the following formula (1) [Chemical formula 1
] (However, in the above formula (1), R1 to R4 are the same or different, and each represents an aliphatic, alicyclic, or aromatic hydrocarbon having 1 to 20 carbon atoms, and R1 to R4 are The total number of carbon atoms contained in the substituents is 12 or more, and X represents a halogen. A thermosetting resin composition characterized in that the ammonium salt is in the range of 0.3 to 3 parts by weight, and the tin-based compound is in the range of 0.001 to 0.25 parts by weight. Claim 2: The quaternary ammonium compound is tetra-n
-butylammonium bromide, tetra-n-butylammonium chloride, n-tetradecyl trisoterammonium chloride or benzalkonium chloride. 3. The composition according to claim 1, wherein the tin compound is di-n-butyltin dilaurate or di-n-butyltin diacetate.