JPS6234948A - Phenolic resin composition - Google Patents

Abstract

PURPOSE:A phenolic resin composition having high heat resistance and improved moldability, obtained by blending two solid resol phenolic resins having a free phenol amount of <= a specific value in a specific ratio and mixing the blend with glass fibers. CONSTITUTION:(A) 100pts.wt. phenolic resin of solid resol phenolic resin having <=7wt% free phenol amount obtained by blending (i) a phenolic resin having 800-1,200 number-average molecular weight (Mn) after removal of free phenol, comprising a phenol nucleus bonded functional group of 20-50mol% methylene group, 10-20mol% methylol group and 40-60mol% dimethylene ether group with (ii) a phenolic resin having 600-1,000Mn, comprising the functional gruop of 30-50mol% methylene group, 30-70mol% methylol group and 0-20mol% dimethylene ether group in a ratio of 3:7-7:3 is blended with (B) 100-250pts.wt. glass fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a phenolic resin composition that has high heat resistance and excellent moldability.

[Prior art]

Traditionally, metal has been widely used for structural parts of automobiles, electrical equipment, and machinery, as well as mechanical parts such as sliding parts, moving parts, and clamping parts, but with the demand for lighter lids and improved productivity, etc. Alternatives to resins with superior processability and appearance are being considered.

These parts require heat resistance, strength, dimensional stability, and chemical resistance, so thermosetting resins are suitable. Examples of thermosetting resins that have excellent moldability and relatively excellent heat resistance include phenolic resins, but conventional phenolic resins have a low heat distortion temperature (ASTh'l D 648).
(The limit is 200 to 230°C), and the use of resin for parts such as automobile engines, brakes, and transmissions, which require higher heat resistance, has been delayed.

In addition, there are thermosetting resins with better heat resistance such as dariimide resin, but dariimide resin is difficult to mold and expensive, and there are few advantages in rolling it and making it into a resin.
Not practical.

[Purpose of the invention]

As a result of research into a resin with high heat resistance and excellent moldability that could not be obtained with conventional thermosetting resins, the present invention uses resol-type phenolic resin as the resin system and glass fiber as the filler. The inventors obtained the knowledge that heat resistance was improved by using the above-described method, and based on this knowledge, they conducted various studies and completed the present invention.

The purpose is to provide a phenolic resin composition that has high heat resistance and excellent moldability.

C Structure of the Invention] The present invention has a free phenol content of 7% by weight or less and a free phenol excluded number average molecular weight (hereinafter abbreviated as un) of 800.
~1200, the phenol core-binding functional group is composed of a methylene group, a methylol group, and a dimethylene ether group,
The ratio of each functional group is 20 to 507% and 10 to 2, respectively.
A solid resol type phenolic resin having 07 ruti and 40 to 607 ruti, the amount of free phenol is 7 weight or less, Mn is 600 to 1000, and the phenol core binding functional group is a methylene group, a methylol group, and a dimethylene ether group. The ratio of each functional group to the solid resol type phenolic resin is 30 to 507%, 30 to 707%, and θ to 20%, respectively, from 3 to 7:
3, 100 parts by weight of phenolic resin, and 1 part of glass fiber.
00 to 250 parts by weight. The ratio of each functional group was determined by NMR measurement after acetylating the resin.

All of the phenolic resins used in the present invention are solid resol type phenolic resins. It is a liquid type, and in order to be applied to molding materials, it is necessary to add a wet cross-ferring process, which is not only more complicated than the normal dry cross-ferring process, but also higher in cost, which is industrially disadvantageous. Become. Phenol resins can be roughly divided into novolac resins that use hexamethylenetetramine as a curing agent, and self-curing resol resins that use methylol groups as curable functional groups.However, due to the reaction mechanism of novolak resins, crosslinking is not possible. Density does not increase sufficiently and high heat resistance cannot be obtained.

Furthermore, all of the solid resol type phenolic resins used in the present invention have a free phenol content of 7% by weight or less. If the amount of free phenol is 7% by weight or more, when applied to a phenolic resin molding material, the reaction will proceed at a relatively low temperature, resulting in poor thermal stability in the cylinder during injection molding, and when the molding material is stored. Problems arise such as changes in 70- or mold smearing during molding due to condensed water.

In addition, the composition of the solid resol type phenolic resin is VIn
is 800~1200. The phenol core-binding functional groups are methylene, methylol, and dimethylene ether groups.
A solid resol-type phenolic resin (hereinafter referred to as dimethylene ether-type resol) made of I# and having a ratio of each functional group of 20 to 507 ruti, 10 to 207 ruti, and 40 to 607 ruti, respectively. , Un is 600-1000. The phenol core-binding functional group is composed of a methylene group, a methylol group, and a dimethylene ether group, and the ratio of each functional group is 30 to 507 ruti, 30 to 707 ruti, and θ, respectively.
The ratio of solid resol type phenolic resin (hereinafter referred to as methane resol) which is ~20 mole is 3 to 7.
:3. Dimethylene ether type resol is
The activation energy is as large as approximately 30 kcat/mot, and the reaction is difficult to proceed at relatively low temperatures, while the reaction tends to proceed at high temperatures, making it suitable for injection molding, whereas methylol-type resols have a high activation energy of the methylol group. The reaction energy is as small as about 10 kcat/mot, and the reaction proceeds at a relatively low temperature, resulting in poor thermal stability within the cylinder during injection molding. In addition, the curing mechanism of dimethylene ether type resols proceeds via a radical reaction, but a proportionate amount of dimethylene ether groups remain due to unreaction or recombination. Since the distance between the phenol nuclei is relatively long, the I-bridge density also increases in methylol-type resols, resulting in poor heat resistance.

Therefore, in order to obtain a resin having high heat resistance and excellent moldability, it is desirable that the blending ratio of the dimethylene ether type resol and the methylol type resol be from 3 to 7:3. If the ratio of dimethylene ether type resol is lower than that of 7;3, injection molding becomes difficult;
However, if the proportion of methylol-type resol is small,
Heat resistance becomes insufficient.

Moreover, glass fiber is used as a filler in the present invention. The glass fiber mentioned here is a chopped strand type fiber having a fiber length of 8 to 15μ and a fine length of 1 to 6III+. The heat resistance is greatly affected by the filler, and molding materials based on organic substances such as wood flour have poor heat resistance, with a heat distortion temperature of 160 to 190°C. Phenol resins containing glass fiber as a filler have high strength against distortion during heating and a small coefficient of thermal expansion, so they have excellent heat resistance, especially thermal shock resistance. It also has the advantage of being excellent in strength, dimensional stability, and chemical resistance. The glass fiber used in the present invention is 10 parts by weight per 100 parts by weight of the phenolic resin.
The range is from 0 to 250 parts by weight, and if it is less than 100 parts by weight, properties such as heat resistance, strength, and dimensional stability will be poor;
If the amount exceeds 50 parts by weight, problems arise in terms of moldability.

Generally, other inorganic fillers, curing aids, mold release agents, pigments, etc. are added to these compositions as necessary, and a molding material is obtained by heating and mixing.

〔Effect of the invention〕

According to the present invention, it is possible to obtain extremely high heat resistance and thermal shock resistance, and also to obtain a molding material with excellent moldability that can be injection molded. It is suitable for parts, especially parts that require high heat resistance such as automobile engines and brakes.

It is also suitable for other electrical components such as commutators and high voltage components that require heat resistance.

Example 1 Dimethylene ether type resol 1 and free 7-el 6. free phenol 4%, Mn 950, and the ratios of methylene group/methylol group and dimethylene ether group are 40 molti, 12 molti, and 48 molti, respectively. 1%
,! In1000, a composition as shown in Table 1 for a phenolic resin in which the ratio of methylene/methylol and dimethylene ether groups is 50 molti, 30 molti, and 20 molti, respectively, and the ratio of methylol type resol 1 is 1:2. After mixing glass fiber and other ingredients, the mixture was kneaded with hot rolls to obtain a molding material. The moldability of this molding material was evaluated using a small molding machine, and the thermal shock resistance was tested using a solder bath. These results are shown in Table 1 along with general characteristics (Examples 2 and 3 and Comparative Examples 1 to 4 are also shown in Table 1).

Example 2 Free phenol 3.7%, Mn 1O00, ratio of methylene group/methylol group and dimethylene ether group:
Dimethylene ether type resol 2 and free phenol 6. 42 molti, 17 molti, and 41 molti, respectively.
8%, un800, the ratio of methylene group/methylol group and dimethylene ether group is 42 mol/3, respectively.
A phenol resin having a ratio of 1:1 to methylol-type resol 2 having a ratio of 8 molty to 20 molty was blended with glass fiber and the like, and materials were prepared and tested in the same manner as in Example 1.

Example 3 Dimethylene ether type resol 3 with free phenol 5%, Mn 850, methylene group/methylol group and dimethylene ether group ratios of 47%, 13% and 40%, respectively, and free phenol 6.2%, un700, Example 1: A phenol resin having a ratio of 2:1 to a methylol type resol 3 having methylene groups, methylol groups, and dimethylene ether groups of 34, 63, and 3, respectively, was blended with glass fiber and the like. 0 Comparative Example 1 A material was prepared and tested in the same manner as in Example 1, using only dimethylene ether type resol 1 as a resin component and blending glass fiber and others.

Comparative Example 2 A material was prepared and tested in the same manner as in Example 1, using only the methylol type resol 3 as the resin component and adding glass fiber bales.

Comparative Example 3 Free Phenol 6,4'16. NYn720, O
A novolak type phenol resin with a /P ratio of 0.7 was used as the resin component, hexamethylenetetramine and glass fiber bales were mixed, and the material was prepared and tested in the same manner as in Example 1.

Comparative Example 4 For a phenolic resin in which the ratio of dimethylene ether type resol 2 and methylol type resol 2 is 1:1,
A material was prepared and tested in the same manner as in Example 1, except that clay and other ingredients were blended without using glass fiber.

Regarding heat resistance, glass transition temperature (200-230℃)
It can be determined based on the coefficient of linear expansion described above and the results of a thermal shock test using an actual semicircular tank.

All of the examples are clearly superior in heat resistance compared to Comparative Example 3, which uses a novolac type phenolic resin, and Comparative Example 4, which does not use glass fiber.

Further, even in Comparative Example 1, in which only dimethylene ether type resol was used as the resin component, it was not able to pass 300°C in the thermal shock test, and the heat resistance was insufficient for use in parts such as automobile engines and brakes.

In addition, all of the Examples have excellent injection moldability and are capable of continuous molding, whereas Comparative Example 2 has insufficient in-cylinder thermal stability and cannot be continuously molded.

In summary, the present invention provides a phenolic resin molding material that has high heat resistance and excellent moldability. The usefulness is obvious.

Measurement method 1. Molding machine using internal thermal stability Minisuit-M32 Molding temperature 175℃ Cylinder temperature 90℃ front, 50℃ rear Evaluation: When the injection waiting time is extended and the injection takes longer than the specified time It is expressed as the waiting time.

2. Thermal shock test specimen: JIS K6911 Charpy test specimen (transfer molding) As shown in Figure 1, the test specimen (1) was heated to a specified temperature using solder (2).
) After immersing the solder in a bathtub for 10 minutes at a solder immersion depth of 3) at 2 to 3 W, the product is placed in water at 20° C. or less within 1 second and allowed to cool for 5 minutes.

Evaluation: Expressed as the maximum temperature at which no cracks occur.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a method of dipping into a solder bath in a thermal shock resistance test. Figure 1

Claims (1)

[Claims] The amount of free phenol is 7% by weight or less, the number average molecular weight excluding free phenol is 800-1200, the phenol core-binding functional group is composed of methylene group, methylol group, and dimethylene ether group, and the ratio of each functional group is 20%.
~50 mol%, 10 to 20 mol%, and 40 to 60 mol% solid resol type phenolic resin, free phenol content is 7% by weight or less, free phenol excluded number average molecular weight is 600 to 1000, and phenol core binding functional group is composed of a methylene group, a methylol group, and a dimethylene ether group, and the ratio of each functional group is 30 to 50.
The ratio of solid resol type phenolic resin is 3:7 to 7: mol%, 30 to 70 mol% and 0 to 20 mol%.
3, 100 parts by weight of phenolic resin, and 1 part of glass fiber.
00 to 2550 parts by weight.