JP4396297B2 - Thermosetting resin composition, thermosetting resin molding material, and cured products thereof - Google Patents

Description

  The present invention relates to a thermosetting resin composition, a thermosetting resin molding material, and a cured product thereof.

  There are 1) novolak-type phenolic resins that are thermoplastic and 2) resol-type resins that are thermosetting, and novolak-type phenolic resins use a curing agent (mainly hexamethylenetetramine as the curing agent). And is used as a thermosetting phenolic resin composition. All of these have various excellent properties such as heat resistance, mechanical strength, and electrical properties, and are used in various applications such as molding materials, laminates, and adhesives.

  On the other hand, the conventional thermosetting phenol resin composition has a problem that the curing rate is slow. Therefore, since it takes time to produce a molded product or a laminate, a thermosetting resin composition that has a high curing speed and can shorten the production time is strongly desired.

  Until now, as a method of increasing the curing rate of the thermosetting phenol resin composition, a high molecular weight novolac type phenol resin is used (for example, refer to Patent Document 1), or a high ortho novolac type phenol resin is used (for example, However, in any case, the effect is insufficient.

  Also, a method of adding an organic acid as a decomposition accelerator for hexamethylenetetramine used as a curing agent has been proposed, but this also has an insufficient effect.

JP 2001-40177 (page 2-4) JP-A-8-302158 (page 2-3)

  An object of the present invention is to provide a thermosetting resin composition having an extremely high curing rate, a thermosetting resin molding material using the same, and a cured product thereof.

  The present inventors have incorporated a novolac-type phenol resin (a), a polyacetal resin (b), and an acidic compound (c) as essential components, so that a thermosetting resin composition and a thermosetting resin having a very high curing rate can be obtained. The present invention has been completed by finding a resin molding material and further studying it.

That is, the present invention
(1) The novolac type phenol resin (a), the polyacetal resin (b), and the acidic compound (c) are essential components, and the novolac type phenol resin (a) and the polyacetal resin (b) A thermosetting resin composition characterized by being melt-mixed at a melting point or higher of (a) and (b) ,
( 2 ) Thermosetting as described in item (1), wherein polyacetal resin (b) is blended at a ratio of 10 parts by weight to 30 parts by weight with respect to 100 parts by weight of novolak-type phenol resin (a). Resin composition,
( 3 ) The thermosetting resin composition according to (1) or ( 2 ), wherein the novolac type phenol resin (a) is a novolac type phenol / formaldehyde resin obtained by reacting phenol with formaldehyde. ,
( 4 ) The thermosetting resin composition according to any one of (1) to ( 3 ), wherein the novolac type phenolic resin (a) has an extraction water electrical conductivity of 50 μS / cm or less. ,
( 5 ) The thermosetting resin composition according to any one of (1) to ( 4 ), wherein the polyacetal resin (b) is a copolymer-type polyacetal resin.
( 6 ) The thermosetting resin composition according to any one of (1) to ( 5 ), wherein the acidic compound (c) is an inorganic acid and / or an organic acid having a dissociation constant pKa of 2 or less. object,
( 7 ) The thermosetting resin composition according to item ( 6 ), wherein the acidic compound (c) is oxalic acid or p-toluenesulfonic acid,
( 8 ) The thermosetting resin according to any one of (1) to ( 5 ), wherein the acidic compound (c) is a compound that releases an acidic substance having a dissociation constant pKa of 2 or less by thermal decomposition. Composition,
( 9 ) The thermosetting resin according to item ( 8 ), wherein the acidic compound (c) is a compound that releases an acidic substance having a dissociation constant pKa of 2 or less by thermal decomposition in a temperature range of 120 ° C to 150 ° C. Composition,
( 10 ) The thermosetting resin composition according to ( 8 ) or ( 9 ), wherein the acidic compound (c) is an aromatic sulfonate cyclohexyl,
( 11 ) The thermosetting resin composition according to item ( 10 ), wherein the acidic compound (c) is cyclohexyl benzenesulfonate;
( 12 ) Acidic compound (c) is cyclohexyl = 4-methylbenzenesulfonate, 3-methylcyclohexyl = 4-methylbenzenesulfonate, 3,5-dimethylcyclohexyl = 4-methylbenzenesulfonate, 4-butylcyclohexyl = 4-methyl. 11 or more selected from benzenesulfonate, 2-isopropyl-5-methylcyclohexyl = 4-methylbenzenesulfonate, 2-hydroxycyclohexyl = 4-methylbenzenesulfonate and 4-hydroxycyclohexyl = 4-methylbenzenesulfonate. ) Thermosetting resin composition,
( 13 ) The thermosetting resin composition according to item ( 12 ), wherein the acidic compound (c) is cyclohexyl = 4-methylbenzenesulfonate;
( 14 ) a thermosetting resin molding material comprising the thermosetting resin composition described in any one of (1) to ( 13 ) and a filler;
( 15 ) A cured product obtained by curing the thermosetting resin composition described in any one of (1) to ( 13 ) or the thermosetting resin molding material described in ( 14 ). ,
Is to provide.

  According to the present invention, a thermosetting resin composition having an extremely fast curing speed can be obtained, which is suitably used for applications in which thermosetting phenolic resin compositions have been conventionally used, such as molding materials, laminates, and adhesives. It is done. Moreover, a thermosetting resin molding material having an extremely high curing rate can be obtained, and a cured product obtained from these materials is suitable for applications such as automotive parts, mechanism parts, electric / electronic parts and the like.

  This invention is a thermosetting resin composition which mix | blends a novolak-type phenol resin (a), a polyacetal resin (b), and an acidic compound (c) as an essential component, By making such a component, a cure rate Is an extremely fast thermosetting resin composition. Further, the present invention is a thermosetting resin molding material having good flowability at molding and an extremely fast curing speed by using the thermosetting resin composition, and the present invention further cures these. It is a cured product obtained.

  The novolac type phenol resin (a) used in the present invention is a phenol resin, cresol resin, xylenol resin, naphthol resin or the like obtained by reacting phenols and aldehydes in the absence of a catalyst or in the presence of a catalyst, Random novolac type and high ortho novolac type can be used, but the fastest curing speed is to use phenol as phenols and phenolic formaldehyde resin obtained by reacting with formaldehyde as aldehydes. Most preferred.

  Further, the novolak type phenol resin (a) preferably has less ionic impurities, and when expressed by the measured value of the extracted water electrical conductivity, a novolak type phenol resin of 50 μS / cm or less is preferable and is close to zero. Is more preferable. When a novolac type phenol resin having a measured value of extracted water electrical conductivity exceeding 50 μS / cm is used, ionic impurities in the novolac type phenol resin are decomposed catalyst of the polyacetal resin during melt mixing with the polyacetal resin. As a result, a curing reaction between the novolac type phenol resin and the polyacetal resin may occur. The measured value of the electrical conductivity of the extracted water in the present invention is 6.0 g of novolak-type phenol resin and 40 ml of distilled water, sealed in a pressure vessel, allowed to cool after heat treatment in a dryer at 125 ° C. for 20 hours, It is obtained by measuring the supernatant water with an electric conductivity meter.

  The polyacetal resin (b) used in the present invention is a polymer compound having an oxymethylene group as a main structural unit, and even a homopolymer type polyacetal resin contains less than 50% by weight of other structural units in addition to the oxymethylene group. Although the copolymer type polyacetal resin may be contained, the copolymer type polyacetal resin is preferable from the viewpoint of thermal stability when the novolac type phenol resin (a) and the polyacetal resin (b) are melt-mixed. The polyacetal resin may contain a release agent, an antioxidant, and the like. As the homopolymer type polyacetal resin, Delrin 500NC010 manufactured by DuPont, Tenac 4010 manufactured by Asahi Kasei, and the like can be used. As the copolymer type polyacetal resin, Duracon M90S manufactured by Polyplastics, F30-01 manufactured by Mitsubishi Engineering Plastics, Tenac C7520 manufactured by Asahi Kasei, and the like can be used.

  The acidic compound (c) used in the present invention may be any of an inorganic acid, an organic acid, a compound that releases an acidic substance by thermal decomposition, etc., but a dissociation constant pKa of 0.5 or more and 2 or less. Preferred are inorganic acids and / or organic acids, and compounds that release an acidic substance having a dissociation constant pKa of 0.5 or more and 2 or less by thermal decomposition or the like. Examples of the inorganic acid and organic acid include sulfuric acid (pKa = 1.6), phosphoric acid (pKa = 2.1), formic acid (pKa = 3.8), oxalic acid (pKa = 1.3), and p-toluene. Sulfonic acid (pKa = 1.7), etc., among which oxalic acid (pKa = 1.3), sulfuric acid (pKa = 1.6), and p-toluenesulfonic acid (pKa = 1.7) Succinic acid and p-toluenesulfonic acid are more preferable, and in a compound that releases an acidic substance having a dissociation constant pKa of 2 or less by thermal decomposition in a temperature range of 120 ° C. to 150 ° C., a dissociation constant of 2 or less As the acidic substance having pKa, for example, the organic acid may be mentioned as long as it is a compound that can be released by thermal decomposition, and cyclohexyl aromatic sulfonates are preferable, and in particular, p-toluene. Benzenesulfonic acid cyclohexyl compounds which release sulfonic acid is more preferable.

  If the dissociation constant pKa is greater than 2, it may be difficult to obtain a sufficient curing rate. On the other hand, if the dissociation constant pKa is smaller than 0.5, the material of the container or mold used for thermosetting may be restricted from the viewpoint of corrosion.

  When the temperature for releasing the acidic substance having a dissociation constant pKa of 2 or less by thermal decomposition is less than 120 ° C., the thermosetting resin composition and the filler are mixed and used as a thermosetting resin molding material. In this case, the fluidity during molding may be reduced, and if it exceeds 150 ° C., it may be difficult to obtain a sufficient curing rate.

  Examples of the aromatic sulfonates that release an acidic substance having a dissociation constant pKa of 2 or less by thermal decomposition in the acidic compound (c) used in the present invention include, for example, cyclohexyl = 4-methylbenzenesulfonate, 2-methylcyclohexyl = 4-methylbenzenesulfonate, 3-methylcyclohexyl = 4-methylbenzenesulfonate, 4-methylcyclohexyl = 4-methylbenzenesulfonate, 4-butylcyclohexyl = 4-methylbenzenesulfonate, 4-cyclohexylcyclohexyl = 4-methylbenzenesulfonate, 2,6-dimethylcyclohexyl = 4-methylbenzenesulfonate, 2,4-dimethylcyclohexyl = 4-methylbenzenesulfonate, 3,4-dimethylcyclohexyl = 4-methylbenzene Zensulfonate, 3,5-dimethylcyclohexyl = 4-methylbenzenesulfonate, 2-isopropyl-5-methylcyclohexyl = 4-methylbenzenesulfonate, 2-hydroxycyclohexyl = 4-methylbenzenesulfonate, 4-hydroxycyclohexyl = 4-methyl Benzene sulfonates such as benzene sulfonate, cyclohexyl = 4-biphenyl sulfonate and 4,4'-bicyclohexyl = bis (4-methylbenzene sulfonate), cyclohexyl = 1-naphthalene sulfonate and cyclohexyl = 2-naphthalene sulfonate, Cyclohexyl naphthalenesulphonate such as benzene sulphonate is preferable, and cyclohexyl = 4-methyl is preferred. Rubenzenesulfonate, 3-methylcyclohexyl = 4-methylbenzenesulfonate, 3,5-dimethylcyclohexyl = 4-methylbenzenesulfonate, 4-butylcyclohexyl = 4-methylbenzenesulfonate, 2-isopropyl-5-methylcyclohexyl = 4- Methylbenzenesulfonate, 2-hydroxycyclohexyl = 4-methylbenzenesulfonate and 4-hydroxycyclohexyl = 4-methylbenzenesulfonate are preferred, and cyclohexyl = 4-methylbenzenesulfonate is particularly preferred.

  As the filler used in the present invention, any of organic fillers, inorganic fillers and the like can be used, but examples of the organic filler include wood powder, plywood powder, thermosetting resin cured powder, and crushed cloth. One or more of these can be used, and inorganic fillers include glass beads, glass powder, calcium carbonate, talc, silica, aluminum hydroxide, clay, mica, etc., glass fibers, carbon Examples include fibrous materials such as fibers, and one or more of these can be used, but are not limited thereto.

  As a compounding quantity of the polyacetal resin (b) in this invention, a preferable lower limit is 10 weight part and a preferable upper limit is 30 weight part with respect to 100 weight part of novolak-type phenol resins (a). If it is less than the lower limit, it may be difficult to obtain a sufficient curing rate. When the upper limit is exceeded, the amount of gas generated during curing increases and the appearance of the cured product may deteriorate.

  As a compounding quantity of the acidic compound (c) in this invention, a preferable lower limit is 0.5 weight part with respect to 100 weight part of novolak-type phenol resins (a), and a preferable upper limit is 20 weight part. If it is less than the lower limit, it may be difficult to obtain a sufficient curing rate. If the upper limit is exceeded, the material of the container and mold used for thermosetting may be restricted from the viewpoint of corrosion.

  As a compounding quantity of the filler in the thermosetting resin molding material of this invention, a preferable lower limit is 30 weight part with respect to 100 weight part of thermosetting resin compositions, and a preferable upper limit is 400 weight part. If it is less than the lower limit value, the mechanical strength of the molded product, which is a cured product of the molding material, may be insufficient. There are things to do.

  In the present invention, in addition to the above components, if necessary, various additives used for thermosetting resins and thermosetting resin molding materials such as silane coupling agents, colorants, flame retardants and mold release agents are blended. be able to.

In the thermosetting resin composition of the present invention, a novolak type phenol resin (a), as a blending method of the polyacetal resin (b), and acidic compound (c), prior to addition and mixing of the acid compound (c), advance, a novolac type phenol resin (a) and polyacetal resin (b) may increase the cure rate to keep the uniform melt-mixed. The melt mixing of the novolac type phenol resin (a) and the polyacetal resin (b) may be performed by stirring and mixing at a temperature higher than the melting point of both in a reaction kettle, or a pressure kneader, a roll, a kneader, a twin screw extruder, etc. You may melt-mix using a kneader.

  As a manufacturing method of the thermosetting resin composition of this invention, a novolak-type phenol resin (a), a polyacetal resin (b), and an acidic compound (c), if necessary, various additives, a known mixer And can be obtained by mixing. The thermosetting resin molding material of the present invention is obtained by adding a filler to the thermosetting resin composition, mixing, kneading using the same kneader, cooling and pulverizing. Can do.

  The mechanism by which the curing rate of the thermosetting resin composition in the present invention is extremely high is not clear, but usually hexamethylenetetramine used as a curing agent for novolak-type phenolic resins decomposes to generate formaldehyde. Compared to the rate, the rate at which polyacetal resin decomposes by the catalytic action of an acidic compound that is a decomposition accelerator to generate formaldehyde is much faster, and the curing reaction between the generated formaldehyde and novolac phenolic resin Is considered to have a catalytic action.

  On the other hand, adding a polyacetal resin to a novolac type phenolic resin has been conventionally known, and adding a phenolic resin as an antioxidant to a polyacetal resin (for example, Japanese Patent Publication No. 49-42662), a polyacetal resin and a novolac. A biaxially stretched film (for example, JP-A-5-98039) having improved stretching stability comprising a type phenolic resin, a method of obtaining a thermoplastic flame retardant polyacetal resin by blending a polyacetal resin with a novolac type phenolic resin ( For example, Japanese Patent Laid-Open No. 2002-212385) is disclosed. In addition, a phenol resin molding material (for example, JP-A-2002-275344) with improved strength containing a novolac-type phenol resin, a polyacetal resin, and a reinforcing material is disclosed. However, all of these are intended to improve the function of the thermoplastic resin by blending with the novolac type phenol resin without decomposing the polyacetal resin, and formaldehyde generated by decomposing the polyacetal resin as in the present invention. This is completely different from a thermosetting resin composition that is cured by reacting with a novolac type phenol resin.

  Furthermore, a method for producing a novolac type phenol resin by reacting a phenol monomer with a polyacetal resin is disclosed (for example, JP-A-58-180515, JP-A-2000-273132, JP-A-2001-122937). Issue gazette). However, all of these use a polyacetal resin as a raw material for producing a novolak-type phenol resin, and use a polyacetal resin as a curing agent for a novolak-type phenol resin as in the present invention. This is completely different from the one obtained from the thermosetting resin composition.

The thermosetting resin composition of the present invention has an extremely fast curing rate and is suitably used for various applications such as molding materials, laminates, and adhesives.
The thermosetting resin composition and thermosetting molding material of the present invention can be made into a cured product by heating to 50 ° C. or higher, desirably 80 to 200 ° C.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited by these examples. In the examples and comparative examples, “parts” and “%” are all “parts by weight” and “% by weight”.

(Synthesis Example 1)
A mixture of 100 parts of phenol, 58 parts of 37% formalin and 1 part of oxalic acid was reacted at 100 ° C. for 3 hours, then dehydrated by atmospheric distillation until the temperature of the reaction mixture reached 140 ° C., and further up to 0.9 kPa, While gradually reducing the pressure, the reaction mixture was distilled under reduced pressure until the temperature of the reaction mixture reached 230 ° C. to remove unreacted phenol, and the novolak type phenol / softening point of 81 ° C. and the extracted water conductivity of 280 μS / cm. 92 parts of formaldehyde resin were obtained.

(Synthesis Example 2)
After reacting a mixture of 100 parts of phenol, 63 parts of 37% formalin and 0.5 part of oxalic acid at 100 ° C. for 3 hours, 10 parts of methanol and 20 parts of distilled water were added and mixed, and allowed to stand for 2 hours. After removing the supernatant of the reaction mixture, it is dehydrated by atmospheric distillation until the temperature of the reaction mixture reaches 140 ° C., and further the pressure of the reaction mixture becomes 230 ° C. while gradually reducing the pressure to 0.9 kPa. Until then, the unreacted phenol was removed by distillation under reduced pressure to obtain 90 parts of a novolac type phenol / formaldehyde resin having a softening point of 80 ° C. and an extracted water electric conductivity of 8 μS / cm.

(Production Example 1)
100 parts of the novolak-type phenol / formaldehyde resin obtained in Synthesis Example 2 and 20 parts of a copolymer-type polyacetal resin (Tenac C4520 manufactured by Asahi Kasei) are melt-mixed at 180 ° C. for 30 minutes, and then placed on a cold bat and rapidly cooled to melt. 118 parts of a mixture were obtained.

(Production Example 2)
In Production Example 1, the molten mixture 118 was used in the same manner as in Production Example 1 except that the novolac type phenol / formaldehyde resin obtained in Synthesis Example 1 was used instead of the novolak type phenol / formaldehyde resin obtained in Synthesis Example 2. Got a part.

(Production Example 3)
100 parts of the novolak type phenol-formaldehyde resin obtained in Synthesis Example 2 and 20 parts of a homopolymer type polyacetal resin (DuPont Delrin 500NC010) were melt-mixed at 190 ° C. for 30 minutes, and then placed on a cold vat and rapidly cooled. 118 parts of molten mixture were obtained.

( Examples 1-3, Examples 7, 8 and Reference Examples 4-6 )
The raw materials blended in the proportions shown in Table 1 were pulverized and mixed in a mortar to obtain a thermosetting resin composition.

(Comparative Examples 1-3)
The raw materials blended in the proportions shown in Table 2 were pulverized and mixed in a mortar to obtain a thermosetting resin composition.

  Using the thermosetting resin composition obtained above, gel time, which is an index of curing speed, was evaluated. The gel time was measured by placing a 1 g sample on a hot plate maintained at 170 ° C., and constantly stirring the spatula while lifting the spatula until the resin composition did not pull the yarn. The shorter this time, the faster the curing rate.

  The results obtained are shown in Table 3.

(Examples 9 and 10 and Comparative Examples 4 and 5)
The raw materials blended in the proportions shown in Table 4 were kneaded with a heating roll, further cooled and pulverized to obtain a molding material.

  Using the obtained molding material, Bacol hardness, which is an index of the curing rate, was measured. The Bacol hardness is expressed by the curing time when a molded product having a thickness of 50 mmφ * 3 mm is formed by injection at a pressure of 20 MPa into a transfer molding die set at 175 ° C., and the Bacol hardness of the molded product becomes 40 or more. . The shorter this time, the faster the curing rate.

  The obtained results are shown in Table 5.

(Examples 11 to 16)
The raw materials blended in the proportions shown in Table 6 were pulverized and mixed in a mortar to obtain a thermosetting resin composition.

The temperature which releases an acid by thermal decomposition of the acidic compound used in Examples 8 and 11 to 16 was determined by TG-DTA measurement.
[Measurement condition]
Equipment: Seiko Instruments TG / DTA220
Temperature range: 30 ° C to 300 ° C (partially stopped)
Temperature increase rate: 10 ° C / min
Atmospheric gas: Nitrogen Sample weight: Approximately 20 mg
The results are shown in Table 7.

  Using the thermosetting resin compositions of Examples 11 to 16, gel time was evaluated in the same manner as in Example 1.

  The obtained results are shown in Table 8.

(Examples 17 to 22)
A molding material was obtained in the same manner as in Example 9 at the ratio shown in Table 9.

  Using the obtained molding material, the Bacol hardness was measured in the same manner as in the evaluation of Example 9.

  The obtained results are shown in Table 10.

  As is clear from the results of Table 3, Table 5, Table 8, and Table 10, the thermosetting resin composition and the thermosetting resin molding material of the present invention obtained results showing a very fast curing rate. .

  Since the curable resin composition and the curable molding material of the present invention have various excellent properties such as heat resistance, mechanical strength, and electrical properties, such as laminates and adhesives. It is suitable for applications in which thermosetting phenolic resin compositions have been used in the past, and in applications such as automotive parts, mechanical parts, and electric / electronic parts that similarly use thermosetting resin molding materials.

Claims (15)

The novolac-type phenol resin (a), the polyacetal resin (b), and the acidic compound (c) are essential components, and the novolac-type phenol resin (a) and the polyacetal resin (b) are preliminarily added to the component (a). And a thermosetting resin composition characterized by being melt-mixed at a melting point or higher of (b) . Against the novolak type phenol resin (a) 100 parts by weight of, at a rate polyacetal resin (b) is less than 30 parts by weight or more 10 parts by weight, by blending claim 1 Symbol placement thermosetting resin composition. Novolak type phenol resin (a) is, according to claim 1 or 2 SL placing thermosetting resin composition of a novolac phenol-formaldehyde resin obtained by reacting phenol and formaldehyde. The thermosetting resin composition according to any one of claims 1 to 3 , wherein the novolak-type phenol resin (a) has an extraction water electric conductivity of 50 µS / cm or less. The thermosetting resin composition according to any one of claims 1 to 4 , wherein the polyacetal resin (b) is a copolymer type polyacetal resin. The thermosetting resin composition according to any one of claims 1 to 5 , wherein the acidic compound (c) is an inorganic acid and / or an organic acid having a dissociation constant pKa of 2 or less. The thermosetting resin composition according to claim 6 , wherein the acidic compound (c) is oxalic acid or p-toluenesulfonic acid. The thermosetting resin composition according to any one of claims 1 to 5 , wherein the acidic compound (c) is a compound that releases an acidic substance having a dissociation constant pKa of 2 or less by thermal decomposition. The thermosetting resin composition according to claim 8, wherein the acidic compound (c) is a compound that releases an acidic substance having a dissociation constant pKa of 2 or less by thermal decomposition in a temperature range of 120 ° C to 150 ° C. Acidic compound (c) according to claim 8 or thermosetting resin composition according 9 is an aromatic sulfonic acid cyclohexyl compounds. The thermosetting resin composition according to claim 10 , wherein the acidic compound (c) is cyclohexyl benzene sulfonate. The acidic compound (c) is cyclohexyl = 4-methylbenzenesulfonate, 3-methylcyclohexyl = 4-methylbenzenesulfonate, 3,5-dimethylcyclohexyl = 4-methylbenzenesulfonate, 4-butylcyclohexyl = 4-methylbenzenesulfonate, 12. The heat according to claim 11 , wherein the heat is one or more selected from 2-isopropyl-5-methylcyclohexyl = 4-methylbenzenesulfonate, 2-hydroxycyclohexyl = 4-methylbenzenesulfonate and 4-hydroxycyclohexyl = 4-methylbenzenesulfonate. Curable resin composition. The thermosetting resin composition according to claim 12 , wherein the acidic compound (c) is cyclohexyl = 4-methylbenzenesulfonate. A thermosetting resin molding material comprising the thermosetting resin composition according to any one of claims 1 to 13 and a filler. A cured product obtained by curing the thermosetting resin composition according to any one of claims 1 to 13 or the thermosetting resin molding material according to claim 14 .