JPH06184405A - Phenol resin composition - Google Patents

Abstract

PURPOSE:To obtain a phenol resin composition composed of a specified ration of a specified dimethylene ether resol type phenol resin and a novolak type phenolic resin and improved in heat stability in a molding cylinder and injection molding properties. CONSTITUTION:This resin composition is obtained by blending 5 to 30 pts.wt. novolak type phenolic resin with 100 pts.wt. dimethylene ether resol type phenol resin exhibiting 500 to 1200 number-average molecular weight, 30 to 50mol% ratio of the dimethylene ether bonds in all the bonded formaldehydes and 70 to 80 deg.C softening point. In addition, <=50 pts.wt. among 100 pts.wt. the dimethylene ether resol type phenol resin is preferably substituted with a methylolresol type phenol resin exhibiting <=30mol% ratio of the dimethylene ether bonds in all the bonded formaldehydes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phenol resin composition used as a molding material composed of a specific resol type phenol resin and novolak type phenol resin.

[0002]

2. Description of the Related Art Resole type phenolic resins are used in a wide range of fields including electric and electronic parts because they have the property of self-curing and do not generate ammonia during curing. Generally, a resol type phenol resin can be roughly classified into a methylol resol type and a dimethylene ether type depending on a functional group bonded to a phenol nucleus. Methylol-type phenolic resin has drawbacks such as low activation energy of curing reaction and progress of reaction even at relatively low temperature, and generating a lot of condensed water during curing. In this case, there is a problem that the thermal stability in the cylinder of the molding machine is poor and the mold is likely to fog. Further, the dimethylene ether resol type phenol resin has relatively good thermal stability and excellent molding stability, but has poor curability, as compared with the methylol resol type phenol resin. On the other hand, the novolak type phenol resin is the most general-purpose phenol resin, but it uses hexamethylenetetramine as a curing agent and has a drawback that generation of ammonia gas is unavoidable during curing.

[0003]

DISCLOSURE OF THE INVENTION The inventor of the present invention has been keenly researched in order to solve the above drawbacks and to obtain a phenol resin composition containing a resol type phenol resin as a main component, which is excellent in curability and thermal stability. As a result, by admixing a specific dimethylene ether resol type phenol resin with a novolac type phenol resin, a phenol resin composition having remarkably excellent thermal stability without deteriorating curability was found, and the present invention was completed. It was done.

[0004]

According to the present invention, the number average molecular weight is 500 to 1200, the proportion of dimethylene ether bonds in the total bound formaldehyde is 30 to 55 mol%, and the softening point is 7.
100 parts by weight of dimethylene ether resol type phenol resin having a temperature of 0 to 80 ° C., a number average molecular weight of 400 to 100
It is a phenol resin composition characterized by being compounded with 5 to 30 parts by weight of a novolac type phenol resin.

The above dimethylene ether resol type phenolic resin has a molar ratio of formaldehyde to phenol (F / P) of 1.0 to 3.0 and is usually used as a catalyst.
(a) a salt of a Group 2 element or transition element with an organic carboxylic acid such as formic acid or acetic acid; and (b) a salt of a Group 2 element or transition element with an inorganic acid such as boric acid, hydrochloric acid or nitric acid alone Alternatively, they are used in combination and then reacted and then dehydrated into a solid form. In the present invention, the number average molecular weight is 500 to 1200 and the melting point is 70 to
80 ° C. is preferred. The proportion of dimethylene ether bonds in the total bound formaldehyde is preferably 30 to 55 mol%. When it is 30 mol% or less, the ratio of methylol bond becomes large and the thermal stability becomes poor, which is not preferable. Free phenol is preferably 5% or less, and 2%
The following are more preferable. If it is 5% or more, the handling becomes difficult due to a decrease in melting point and solidification due to moisture absorption. Further, when it is used as a molding material, it causes fog of the molding die.

As the phenol resin, it is possible to replace 50 parts by weight or less of the above dimethylene ether resol type phenol resin with a resol type phenol resin other than the above, and this case is also included in the present invention. In the present invention, by using a dimethylene ether resol type phenol resin in combination with a novolac type phenol resin, it is possible to improve the thermal stability without lowering the curability.
As the novolac type phenol resin used, a commercially available one can be used, but one having a number average molecular weight of 400 to 1,000 is preferable because the viscosity and melting point are appropriate and it is easy to handle.
The compounding amount is preferably 5 to 30 parts by weight based on the resole resin. If it is 5 parts by weight or less, the effect of improving the thermal stability is not sufficient, and if it exceeds 30 parts by weight, curing tends to decrease.

Further, the present invention is preferably used in combination with a known curing aid. Calcium hydroxide and magnesium hydroxide can be used as the curing aid. The blending amount is preferably 2 to 7 parts by weight with respect to the phenol resin. If it is 2 parts by weight or less, the effect is small, and if it is 7 parts by weight or more, curing is too fast to obtain a good cured product. Further, as other additives, fillers, pigments, lubricants and the like can be added. As the filler, wood powder, calcium carbonate, glass fiber, asbestos or the like can be used alone or in combination.

[0008]

EXAMPLES Next, the phenol resin composition of the present invention will be specifically described with reference to Examples and Comparative Examples. <Production Example of Dimethylene Ether Resol-Type Phenolic Resin> 1 mol of phenol and 1.5 mol of paraformaldehyde were blended, and barium acetate and zinc nitrate as catalysts were present at 0.9 and 0.35% by weight, respectively, with respect to phenol,
After carrying out the reaction while removing water at 120 ° C. for 4 hours, 1
It was aged at 05 ° C for 1 hour and taken out. The obtained phenol resin is a solid resol-type phenol resin having 43% of dimethylene ether groups, a number average molecular weight of 750, a melting point of 75 ° C.,
It was 1.8% free phenol.

Examples 1 and 2 The above-mentioned dimethylene ether resol type phenol resin and a novolac type phenol resin having a number average molecular weight of 900 and a melting point of 92 ° C. or a methylol resole type phenol resin having a number average molecular weight of 450 and a melting point of 85 ° C. are used. The proportions shown in Table 1 were added. To 100 parts by weight of these phenolic resins, 100 parts by weight of wood powder, 4 parts by weight of calcium hydroxide as a curing aid and 4 parts by weight of a pigment were blended, kneaded with a hot roll, cooled and pulverized to obtain a molding material. . <Examples 3 and 4> The above-mentioned dimethylene ether resol type phenol resin and a novolak type phenol resin having a number average molecular weight of 900 and a melting point of 92 ° C, or a methylol resole type phenol resin having a number average molecular weight of 450 and a melting point of 85 ° C are shown in Table 1. It was mixed in the ratio of. These phenolic resins 1
130 parts by weight of glass fiber, 3 parts by weight of magnesium hydroxide as a hardening aid, 4 parts by weight of a lubricant and a pigment were mixed with 00 parts by weight, kneaded with a hot roll, cooled and pulverized to obtain a molding material. << Comparative Examples 1 and 2 >> As shown in Table 1, a phenol resin molding material was obtained in the same manner as in Examples without blending the novolac type phenol resin.

The results obtained in these Examples and Comparative Examples are shown in Table 1.

[Table 1]

(Measurement method) Using the molding materials obtained in the above Examples and Comparative Examples, the mold temperature was 175 ° C. and the molding pressure was 80.
A disc test piece having a diameter of 50 mm and a thickness of 3 mm was prepared at kg / cm ² , and the degree of curing was measured by a Barcol hardness meter (No. 935). On the other hand, the thermal stability in the cylinder of the injection molding machine was evaluated by setting the mold temperature of the mini super M32 molding machine to 175 ° C.
Set the cylinder tip to 90 ° C and the terminal end to 50 ° C, extend the injection waiting time, and set the specified injection time to 5 seconds. Represent

[0012]

As is clear from the above examples, the phenol resin composition of the present invention can be used in the molding machine cylinder by blending the novolac type phenol resin while taking advantage of the self-curing property of the resol type phenol resin. It is possible to sufficiently enhance the thermal stability and injection moldability of the above.

Claims (2)

[Claims] 1. A number-average molecular weight of 500 to 1200, and the proportion of dimethylene ether bonds in the total bound formaldehyde is 3.
0 to 55 mol% and 100 parts by weight of dimethylene ether resol type phenol resin having a softening point of 70 to 80 ° C.,
A phenol resin composition comprising 5 to 30 parts by weight of a novolac type phenol resin. 2. 50 parts by weight or less of 100 parts by weight of the dimethylene ether resol-type phenolic resin has a dimethylene ether bond ratio of 30 in total bound formaldehyde.
A phenol resin composition, characterized in that it is substituted with a methylol resole type phenol resin in an amount of less than or equal to%.