JP2007119611A - Phenolic resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phenolic resin composition excellent in the balance of cure rate and heat resistance and preventing curing inhibition even in blending of basic fillers by using substantially no hexamethylenetetramine. <P>SOLUTION: The phenolic resin composition comprises a novolak-type phenolic resin (a), a polyacetal resin (b) and an organic base compound (c) as essential components and comprises substantially no hexamethylenetetramine. Preferably, the organic base compound (c) contains phosphorus and/or nitrogen and further contains a compound having a boiling point of 150°C or higher. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a phenol resin composition.

  There are two types of phenolic resins: novolak-type phenolic resins and resol-type phenolic resins. Novolak-type phenolic resins contain a curing agent (mainly hexamethylenetetramine is used as a curing agent) and are thermosetting phenolic resins. Used as a 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.

  Since hexamethylenetetramine used as a curing agent is a solid, it is particularly preferably used in applications that require a powder form as a product form. On the other hand, hexamethylenetetramine is a mutagenic substance, and ammonia is generated during curing, which has the problem of corroding copper, zinc, tin, and their alloys. It is rare.

  So far, epoxy resins and isocyanates have been studied as curing agents for novolak-type phenolic resins instead of hexamethylenetetramine, but they are hardened and heat-resistant, and solidified when the resin is used in powder form. There has not yet been found a curing system that combines rusticity and the like.

  As a curing system having these characteristics, an example in which polyacetal is used as a curing agent and acid is used as a catalyst has been reported (for example, see Patent Document 1). A system using polyacetal as a curing agent is excellent in curability and heat resistance, and has a characteristic that it is difficult to consolidate because the curing agent is a high molecular weight resin, and it is particularly suitable for molding materials. it can. On the other hand, in applications that dislike metal corrosion, for example, friction materials, grindstones, abrasive cloths, etc., a basic substance is added to the filler. In order to develop these applications, there is a demand for a catalyst that does not inhibit curing even when a basic substance is blended.

JP 2004-269856 A

  The present invention provides a phenolic resin composition that is excellent in the balance between curing speed and heat resistance without substantially using hexamethylenetetramine, and that does not inhibit curing even when a basic filler is blended.

Such an object is achieved by the following present inventions (1) to (9).
(1) A phenol resin composition comprising novolac-type phenol resin (a), polyacetal resin (b), and organic base compound (c) as essential components and substantially free of hexamethylenetetramine.
(2) The phenol resin composition according to (1), wherein the organic base compound (c) contains phosphorus and / or nitrogen.
(3) The organic base compound (c) is an imidazole, alcoholamine, hydroxylamine, alkylphosphine, arylphosphine, 1,8-diazabicyclo- [5.4.0] -undec-7-ene. The phenol resin composition according to (1) or (2), which is at least one selected from the group consisting of
(4) The content of the organic base compound (c) is 0.5 to 20 parts by weight with respect to 100 parts by weight of the novolak type phenol resin (a), according to any one of (1) to (3). Phenol resin composition.
(5) The phenol resin composition according to any one of (1) to (4), wherein the organic base compound (c) has a boiling point of 150 ° C. or higher.
(6) The phenol resin composition according to any one of (1) to (5), wherein the novolac type phenol resin (a) and the polyacetal resin (b) are previously melt-mixed.
(7) The phenol resin composition according to any one of (1) to (6), wherein the polyacetal resin (b) dispersed in the phenol resin composition has an average particle size of 150 μm or less.
(8) The phenol according to any one of (1) to (7), wherein the content of the polyacetal resin (b) is 5 to 30 parts by weight with respect to 100 parts by weight of the novolac type phenol resin (a). Resin composition.
(9) The phenol resin composition according to any one of (1) to (8), wherein the polyacetal resin (b) includes a homopolymer type polyacetal resin.

According to the present invention, the novolac type phenol resin (a), the polyacetal resin (b), and the organic base compound (c) are essential components, and the curing rate and heat resistance are substantially reduced without using hexamethylenetetramine. A phenol resin composition excellent in balance can be provided.
Further, by using an organic base compound containing phosphorus and / or nitrogen as the organic base compound (c), the curing rate can be particularly improved.
Furthermore, the novolac-type phenol resin (a) and the polyacetal resin (b) are melt-mixed in advance and the average particle size of the polyacetal resin (b) dispersed in the composition is reduced to 150 μm or less to further increase the curing rate. Can be improved.

The phenol resin composition of the present invention will be described.
The phenol resin composition of the present invention (hereinafter sometimes simply referred to as “composition”) is essentially composed of a novolac type phenol resin (a), a polyacetal resin (b), and an organic base compound (c) as essential components. Is characterized by not containing hexamethylenetetramine.

  The novolak type phenol resin (a) used in the composition of the present invention is not particularly limited, but is a phenol resin, cresol resin, or xylenol resin obtained by reacting phenols and aldehydes in the absence of a catalyst or in the presence of a catalyst. , Naphthol resin, and the like, and can be used in either a random novolac type or a high ortho novolak type.

The composition of the present invention is characterized by using a polyacetal resin (b). By using the polyacetal resin (b), the novolac type phenol resin (a) can be cured without substantially using hexamethylenetetramine. That is, the polyacetal resin (b) can be used as a curing agent for the novolak type phenol resin (a).
In the composition of the present invention, the mechanism by which the novolak type phenol resin (a) can be cured substantially without using hexamethylenetetramine is not clear, but if the polyacetal resin is an acidic substance, the polyacetal is decomposed into formaldehyde. It is confirmed that the decomposition of organic base compounds described later is promoted in the same manner, formaldehyde is generated, and the generated formaldehyde cures the novolak type phenol resin. That is, it is presumed that the organic base compound acts as a catalyst as a mechanism for the reaction between formaldehyde and the novolac type phenol resin.
In addition, the fact that hexamethylenetetramine is not substantially used here refers to 1 part by weight or less with respect to 100 parts by weight of the novolak type phenol resin (a) used.

  The polyacetal resin (b) used in the composition of the present invention is a polymer compound having an oxymethylene group as a main structural unit, and is not particularly limited. However, the homopolymer type polyacetal resin also has other components in addition to the oxymethylene group. A copolymer-type polyacetal resin containing less than 50% by weight of units may be used. Among these, homopolymer type polyacetal resin is preferable in terms of curability.

The polyacetal resin (b) may contain a release agent, an antioxidant, a stabilizer, and the like. Examples of commercially available products of the homopolymer type polyacetal resin include Delrin 500NC010 manufactured by DuPont, Asahi Kasei Tenac 4010, etc. can be used.
Moreover, as a commercial item of the said copolymer type polyacetal resin, polyplastics Duracon M90S, Mitsubishi engineering plastics company F30-01, Asahi Kasei Tenac C7520, etc. can be used, for example. These polyacetals may be used alone or in combination of two or more.

  The polyacetal resin (b) is preferably melt-mixed in advance with the novolac phenol resin (a). By doing so, since the polyacetal resin and the organic base compound react quickly, the curing rate can be particularly improved.

  Furthermore, the average particle size of the polyacetal resin (b) dispersed in the composition of the present invention is preferably 150 μm or less. More preferably, it is 130 μm or less. Thereby, since a polyacetal resin and an organic base compound react rapidly, a cure rate can be improved.

  It is preferable that content of the said polyacetal resin (b) is 5-30 weight part with respect to 100 weight part of novolak-type phenol resins (a). More preferably, it is 10-20 weight part. By setting the content of the polyacetal resin (b) in the above range, a sufficient curing rate can be obtained, and the appearance of the cured product can be improved by suppressing the amount of gas generated during curing.

  The method for dispersing the average particle size of the polyacetal resin (b) in the composition at 150 μm or less is not particularly limited, but the average particle size is not more than 150 μm in advance by, for example, a jet mill or freeze pulverization. The mixture may be mixed and dispersed, or added when kneading into a resin or when the composition is pulverized, and by applying a mechanical force, the final particle size in the composition is 150 μm or less. You may make it disperse | distribute. Alternatively, the novolac-type phenol resin (a) may be melted and mixed in advance by maintaining the melting point of the two or more with a reaction kettle, a pressure kneader, a roll, a kneader, a twin screw extruder or the like.

The average particle diameter of the average polyacetal resin (b) can be measured by adding a resin mixture obtained by mixing a polyacetal resin in methanol and recovering the polyacetal from the insoluble portion.
Although it does not specifically limit as said measuring method, It can measure with a laser diffraction / scattering type particle size distribution measuring apparatus and a dynamic light scattering type particle size distribution measuring apparatus, and it is a thing like an electron micrograph, and observes directly. You can also. In the phenol resin composition of the present invention, the average particle size was measured using a laser diffraction / scattering particle size distribution analyzer.

  The organic base compound (c) used in the composition of the present invention is not particularly limited, but preferably contains phosphorus and / or nitrogen. More preferably, those containing nitrogen are, for example, imidazoles, alcohol amines, hydroxylamines, 1,8-diazabicyclo- [5.4.0] -undec-7-ene, and those containing phosphorus, For example, alkyl phosphines and aryl phosphines. Thereby, a cure rate can be improved rather than the case where another organic base compound is used. These compounds may be used alone or in combination of two or more.

  The content of the organic base compound (c) in the composition of the present invention is preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of the novolac type phenol resin (a). More preferably, it is 1 to 15 parts by weight. By setting the content of the organic base compound (c) in the above range, a sufficient curing rate can be obtained, and mechanical strength and heat resistance can be improved.

  Further, the boiling point of the organic base compound (c) used in the composition of the present invention is preferably 150 ° C. or higher. More preferably, it is 160 degreeC or more. By using the organic base compound (c) having a boiling point equal to or higher than the above temperature, the curability can be particularly improved.

The blending method of the composition of the present invention is not particularly limited. For example, when the organic base compound (c) is solid, the novolak type phenol resin (a) and the polyacetal resin (b) are mixed in the reaction kettle. After melt mixing above the melting point of the both, the organic base compound (c) may be mechanically mixed using a kneader such as a pressure kneader, roll, kneader, or twin screw extruder, or mixed during pulverization. It doesn't matter. In addition, after the organic base compound (c) is mechanically mixed with the novolac type phenol resin (a) using a melt mixing or kneader, the polyacetal resin (b) may be mixed with a kneader or a pulverizer. Absent. Further, the novolac type phenol resin (a), the polyacetal resin (b), and the organic base compound (c) may be kneaded at once or mixed and added at the time of pulverization.
When the organic base compound (c) is liquid, the organic base compound (c) can be added to the novolac type phenol resin (a) by melting or kneading in advance, or the novolac type phenol resin (a), polyacetal resin can be added. (B) The organic base compound (c) can be kneaded and mixed together.

  As described above, the composition of the present invention contains the polyacetal resin (b). On the other hand, it is conventionally known to add a polyacetal resin to a novolac type phenol resin. Is added to the polyacetal resin as an antioxidant (for example, Japanese Patent Publication No. 49-42662), and a biaxially stretched film having improved stretching stability (for example, JP-A-5-42626) comprising a polyacetal resin and a novolac type phenol resin. No. 98039) and a method for obtaining a thermoplastic flame-retardant polyacetal resin by blending a polyacetal resin with a novolac-type phenol resin (for example, JP-A-2002-212385) is disclosed. However, these are all intended to improve the function of the thermoplastic resin by blending with a novolac type phenol resin without decomposing the polyacetal resin, and the polyacetal resin is decomposed like the composition of the present invention. The organic base compound (c) acts as a catalyst on the generated formaldehyde, and is completely different from the phenol resin composition which is cured by reacting with the 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 them use a polyacetal resin as a raw material for producing a novolak type phenolic resin, and what uses a polyacetal resin as a curing agent for a novolak type phenolic resin like the composition of the present invention. It is completely different.

  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 1000 parts of phenol, 710 parts of 37% formalin and 10 parts of oxalic acid was reacted at 100 ° C. for 3 hours, and 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, dehydration was performed by distillation under reduced pressure until the temperature of the reaction mixture reached 240 ° C. to obtain 1121 parts of a novolac type phenol / formaldehyde resin.

(Production Example 1)
100 parts of the novolak type phenol / formaldehyde resin obtained in Synthesis Example 1 and 20 parts of a homopolymer type polyacetal resin (Tenac 4010 manufactured by Asahi Kasei Co., Ltd.) are melt-mixed at 190 ° C. for 10 minutes, and then placed on a cold vat and rapidly cooled. , 98 parts of mixture A were obtained. A part of the obtained resin was added to methanol to recover the insoluble polyacetal, but the polyacetal resin was in the form of an agar-like gel and the average particle size was not measurable.

(Production Example 2)
100 parts of the novolak type phenol / formaldehyde resin obtained in Synthesis Example 1 and 20 parts of homopolymer type polyacetal resin (Derlin 500NC010 manufactured by DuPont) were kneaded 30 times with a heated roll kneader at a roll temperature of 90 ° C. The plate was cooled to obtain 112 parts of the mixture B. When a part of the obtained resin was added to methanol to recover insoluble polyacetal, the average particle size of the polyacetal resin was 31 μm.

(Production Example 3)
1000 parts of homopolymer type polyacetal resin (Tenac 4010 manufactured by Asahi Kasei Co., Ltd.) was pulverized by a jet mill to obtain 158 parts of polyacetal resin powder. The average particle size of this polyacetal resin powder was 54 μm.

Table 1 shows the blending amounts of the raw materials used in Examples and Comparative Examples. All numbers are parts by weight.
(Example 1) 120 parts of the mixture A obtained in Production Example 1 and 7 parts of triethanolamine as an organic base compound were ground and mixed in a mortar to obtain a composition.

(Example 2) A composition was obtained in the same manner as in Example 1 except that instead of the mixture A, the mixture B obtained in Production Example 2 was used.

(Example 3) A composition was obtained in the same manner as in Example 1 except that 100 parts of the novolak-type phenol resin obtained in Synthesis Example 1 and 10 parts of the polyacetal resin powder obtained in Production Example 3 were used.

(Example 4) A composition was obtained in the same manner as in Example 3 except that the amount of polyacetal resin powder was increased to 20 parts.

(Example 5) A composition was obtained in the same manner as in Example 3 except that the amount of polyacetal resin powder was increased to 30 parts.

(Example 6) A composition was obtained in the same manner as in Example 1 except that 2-methylimidazole was used instead of triethanolamine.

(Example 7) A composition was obtained in the same manner as in Example 1 except that 1,8-diazobicyclound-7-ene was used instead of triethanolamine.

(Example 8) A composition was obtained in the same manner as in Example 1 except that triphenylphosphine was used instead of triethanolamine.

(Example 9) A composition was obtained in the same manner as in Example 1 except that 50 parts of calcium carbonate was additionally blended.

(Comparative Example 1) 100 parts of the novolak type phenolic resin obtained in Synthesis Example 1 and 10 parts of hexamethylenetetramine were pulverized and mixed in a mortar to obtain a composition.

(Comparative Example 2) The novolak type phenolic resin obtained in Synthesis Example 1 was reduced to 50 parts, and 50 parts of epoxy resin (EOCN-103S manufactured by Nippon Kayaku Co., Ltd.), 1 part of triphenylphosphine, and hexamethylenetetramine were not used. A composition was obtained in the same manner as in Comparative Example 1 except that.

(Comparative example 3) Instead of the novolak-type phenol resin obtained in Synthesis example 1, 120 parts of the mixture A obtained in Production example 1, 2 parts of oxalic acid, and hexamethylenetetramine were not used. A composition was obtained in the same manner.

(Comparative Example 4) A composition was obtained in the same manner as in Comparative Example 3 except that 50 parts of calcium carbonate was added.

Evaluation Method (1) Gelation Time: Based on JIS K 6910, 0.5 g of resin was used and measured with a 165 ° C. hot platen.

(2) Fixed carbon: In accordance with JIS M 8812, the composition was heated and dried at 135 ° C. for 1 hour, then carbonized at 430 ° C. for 30 minutes, and then ashed at 800 ° C. for 30 minutes. From the weight after the treatment, it was calculated by the following formula.
Fixed carbon (% by weight) = (weight after carbonization) − (weight after ashing) / (weight after drying) × 100

  About the phenol resin composition obtained in Examples 1-9 and Comparative Examples 1-4, the gelation time which is a standard of a cure rate was measured, and sclerosis | hardenability was compared. Moreover, about Examples 1-8 and Comparative Examples 1-3, the fixed carbon which is a heat resistant standard was measured and evaluated. The results are shown in Table 2.

As is clear from the results in Table 2 above, the phenol resin composition of the present invention comprising novolac type phenol resin (a), polyacetal resin (b), and organic base compound (c) as essential components is hexamethylenetetramine. Although it was not used, it had excellent curing speed and heat resistance, had heat resistance comparable to hexamethylenetetramine, and excellent balance between curing speed and heat resistance. In addition, since Examples 3 to 5 using polyacetal as a curing agent use an organic base compound, the gelation time is practically not problematic as compared with Comparative Example 3 using oxalic acid as a catalyst. I was able to. Further, in Example 9, a resin composition in which curability did not decrease despite the presence of a basic filler such as calcium carbonate could be obtained. On the other hand, Comparative Example 4 containing calcium carbonate similarly had a long gelation time because it did not contain an organic base compound.

Claims (9)

A phenol resin composition comprising a novolac type phenol resin (a), a polyacetal resin (b), and an organic base compound (c) as essential components and substantially free of hexamethylenetetramine. The phenol resin composition according to claim 1, wherein the organic base compound (c) contains phosphorus and / or nitrogen. The organic base compound (c) is selected from imidazoles, alcoholamines, hydroxylamines, alkylphosphines, arylphosphines, 1,8-diazabicyclo- [5.4.0] -undec-7-ene. The phenol resin composition according to claim 1, wherein the phenol resin composition is one or more selected. Content of the said organic base compound (c) is 0.5-20 weight part with respect to 100 weight part of novolak-type phenol resins (a), The phenol resin composition in any one of Claims 1-3 . The phenol resin composition according to claim 1, wherein the organic base compound (c) has a boiling point of 150 ° C. or higher. The phenol resin composition according to any one of claims 1 to 5, wherein the novolac-type phenol resin (a) and the polyacetal resin (b) are previously melt-mixed. The phenol resin composition in any one of Claims 1-6 whose average particle diameter of the said polyacetal resin (b) currently disperse | distributed in the said phenol resin composition is 150 micrometers or less. Content of the said polyacetal resin (b) is 5-30 weight part with respect to 100 weight part of said novolak-type phenol resins (a), The phenol resin composition in any one of Claims 1-7. The phenol resin composition according to any one of claims 1 to 8, wherein the polyacetal resin (b) contains a homopolymer type polyacetal resin.