JPS5911339A - Phenolic molding material for lowly expanded foam - Google Patents

Abstract

PURPOSE:To provide a phenolic molding material which is suitable for use in the production of heat insulating sheet, etc. and gives lowly expanded moldings which are lightweight and excellent in strength, appearance, etc. by compression molding, by blending seed hull cellulose powder and a blowing agent with a phenolic resin. CONSTITUTION:100pts.wt. phenolic resin (A) such as novolak or resol type phenolic resin, 40-400pts.wt. seed hull cellulose powder (B) having an apparent volume of 30-80cc/20g such as rice hull, peanut hull, back wheat chaff or bean hull and a blowing agent (C) having a decomposition temp. of 120-180 deg.C in the presence of the phenolic resin are mixed together in such a proportion as to give 0.2-5pts.wt. component C per 100pts.wt. of the combined amount of components A and B to obtain the desired phenolic molding material for lowly expanded foam.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a low-foaming phenolic resin molding material, more specifically, a low-foaming phenolic resin molding material that has sufficient strength and good appearance to withstand normal use by compression molding, and has a specific gravity of 1.0 or less. The present invention relates to a phenolic resin molding material that provides a foamed molded product.

Conventionally, foam molded products using phenolic resin are well known as highly foamed materials used for insulation materials, etc., but the appearance and strength of these highly foamed materials themselves are relatively neglected. It can be easily produced by utilizing the properties of phenol resin, such as its melt fluidity. On the other hand, low-foaming phenolic resin molded products are not well known, and some are commercially available as low-foaming phenolic resin molding materials, but the molding conditions are complex and require a long molding time, and they are difficult to obtain. The specific gravity of the foamed molded product is much higher than 1.0, and there are problems such as not being able to reduce the weight very much, so it has not been widely used.

In general, low-foam materials are used for containers, shellfish, heat insulating boards, etc. that are used on a daily basis, and are required to have strength depending on the purpose. For example, the apparent specific gravity is 0.2 to 1
It is desirable to have a relatively light weight and a good appearance.

In the course of research to develop a method for producing such low-foaming phenolic resin molded articles, the present inventors discovered that the fluidity of the phenolic resin before and after foaming is greatly affected by the filling base material, and that the formation of closed cells is inhibited. I learned that it is significantly affected. Generally, a cellulose base material is used as a filler in phenolic resin molding materials. It has been found that the foamable phenolic resin molding material containing the resin has extremely poor melt fluidity during foaming, making it extremely difficult to mold a desired foam. The reason for this is not clear, but base materials with a large apparent volume have poor wettability with phenolic resin, and also inhibit the fluidity of phenolic resin molding materials, causing the generated microbubbles to collapse and become large. It is estimated that the formation of air bubbles or open air cells reduces the strength of the foam molded product, and also causes degassing, bubble breakage, and blisters on the surface, which impairs the appearance. It has been found that it is preferable for the base material to be filled to have a relatively small apparent volume.

In addition, phenolic resin molding materials for foams are usually heated under pressurized conditions in a mold to fluidize the material, and then the foaming agent thermally decomposes to release gas, forming a foam and forming the mold. As the space is filled, the phenolic resin is thermoset 7 and molded into the desired foam. In the production of such foams, the time from softening of the phenol resin to hardening and the relationship between its fluidity and the point of gasification of the blowing agent are extremely important, although they are also related to heating and pressurizing conditions. If the blowing agent decomposes too quickly or too slowly, the desired closed cell grown form will not be obtained.

In this way, for phenolic resin foam molding materials, the relationship between the filling base material and the foaming agent is extremely important, and especially when it comes to molding low-foam products, their delicate and important relationship has been neglected. Conventionally known low-foaming phenolic resin molding materials have severely limited molding conditions, making it difficult to easily obtain good foam molded products.

The present inventors have developed a phenolic resin molding material that can easily produce desired low-foam molded products under a wide range of relaxed molding conditions, based on the above findings, using a wide variety of base materials, foaming agents, etc. As a result of repeated experiments and research, a molding material with excellent practicality was discovered, and the present invention was completed.

That is, the present invention decomposes a seed shell cellulose powder having an apparent volume of 30 to 80 cc/201 to a phenol resin at a ratio of 40 to 400 parts by weight per 100 parts by weight of the phenol resin, and in the coexistence with the phenol resin. A blowing agent at a temperature of 120 to 180°C is added in an amount of 0.2 to 5.
The object of the present invention is to provide a low-foaming phenolic resin molding material characterized in that each of the above components is contained in a proportion of 0 parts by weight.

In the present invention, low foaming means that the foaming ratio is about 1.1 to 5 times, and the obtained low foaming molded product itself has sufficient strength to withstand normal use and has a specific gravity. about i
, o or less, preferably 0.2 or more.

The phenolic resin used in the molding material of the present invention is a mixture of phenol resins generally used in phenolic resin molding materials, such as phenols such as phenol and cresol, and aldehydes such as formalin and paraformaldehyde in a predetermined molar ratio. Blend 1. Novolac type phenolic resin, sodium hydroxide, ammonia,
All resol-type phenolic resins obtained by condensation reaction under a basic catalyst such as an amine are encapsulated.

The base material used in the material of the present invention is seed shell cellulose powder with an apparent volume of 30 to 80 CC720F, and examples of the seed shell cellulose include rice husk, peanut shell, buckwheat shell, and bean shell. These can be pulverized to form a powder with an apparent volume within the above range. These may be used alone or in combination of two or more. The apparent volume of the seed husk cellulose powder used as a filling base material is 30f C/202
If the strength is less than 80, the strength of the molded product obtained is insufficient.
If it exceeds cc/2Or, the melt fluidity of the phenolic resin molding material will be inhibited, which is not preferable.

A more preferable apparent volume is 40 to 70 CC/202. Still, the seed husk cellulose powder base material is 80-20
It is more preferable that the mesh be adjusted to about 0 mesh.

In the material of the present invention, if it is desired to improve the low-foamed molded product, for example, even higher impact strength, bending strength, or other properties, other organic or inorganic powder bases may be used as reinforcing or modifying materials. Additional materials can be used. However, even when such a base material is added, the average apparent volume of the total of the seed husk cellulose powder base material and the additional base material is 3.
It is important that the volume is 0.about.80 cc/2 oy, and the apparent volume must be controlled within the above range by re-preparing the additional base material powder or the amount added.

Such additional base materials include organic ones such as wood flour, pulp, wheat flour, etc., and inorganic ones such as pulp, wheat flour, etc.
Examples include heavy calcium carbonate, silica, and asbestos. These may be used alone, but they can be used in combination of two or more.

Further, the blowing agent used in the present invention is a blowing agent having a decomposition temperature of 120°C to 180°C, preferably 125°C to 160°C when coexisting in the molten state of the phenolic resin. Although this decomposition temperature does not necessarily match the decomposition temperature of blowing agents generally described in literature, it can be easily confirmed by simple experiments. The blowing agent that can be suitably used in the molding material of the present invention is sulfonyl hydrazide or its derivatives, among which the most suitable one is para-toluenesulfonyl hydrazone. Note that these foaming agents are usually used alone, but two or more kinds can also be used in combination to adjust the timing of foaming.

The low-foaming phenolic resin molding material of the present invention is formed by blending a phenolic resin with the above-mentioned seed shell cellulose powder or a base material obtained by adding another powder base material to the seed shell cellulose powder, and a foaming agent. Seed husk cellulose powder contains phenolic resin 1
It is blended at a ratio of 40 to 400 parts by weight per 00 parts by weight. If it is less than 40 parts by weight, the strength of the resulting foamed molded product will be insufficient; if it exceeds 400 parts by weight, the melt flowability of the molding material will be insufficient and a good molded product will not be obtained. The preferred blending ratio of the powder base material is 5 parts per 100 parts by weight of phenolic resin.
It is 0 to 200 parts by weight. However, the total amount of the blowing agent including the phenolic resin and the seed shell cellulose powder base material is 100%.
It is necessary to contain it in a ratio of 0.2 to 5.0 parts by weight per part by weight. The amount of the foaming agent to be added is selected depending on the desired expansion ratio of the resulting low foamed product, but if it is less than 0.2 parts by weight, a molded product with an expansion ratio of 1.1 or more cannot be obtained, and if it is more than 5 parts by weight, This is unsuitable because open air bubbles are formed.

The low-foaming phenolic resin molding material of the present invention contains additives normally used in phenolic resin molding materials, such as hardening aids such as calcium hydroxide and magnesium oxide;
Additives such as a mold release agent 1 such as stearic acid, a metal salt of stearate, and wax, a coloring agent, and a surfactant such as silicone may be added as desired.

The molding material of the present invention can be produced by a method generally used for preparing phenolic resin molding materials,
For example, a solvent such as methanol is added to the blended chain components of the above composition, and the mixture is mixed using a mixer, and the resulting mixture is kneaded with heated rolls, then formed into a sheet, and granulated or pulverized to an appropriate particle size. It can be prepared by:

In order to produce a low-foam molded article using the molding material of the present invention, a predetermined amount of the material prepared as described above is heated at 130°C to 1°C.
It is obtained by compression molding in a mold heated to 80° C. for 5 to 15 minutes, depending on the thickness of the molded product.

The phenolic resin molding material of the present invention can be produced by compression molding.
, Daily Use] 7) It is highly practical as it can easily produce a low-foamed molded product that has sufficient strength and good appearance and has a specific gravity of 1.0 or less. therefore,
The phenolic resin molding material of the present invention can be used for various purposes such as low specific gravity containers with a wood texture, wood-like decorations, wood-like toys, and heat-resistant and creep-free insulation materials or insulation boards, and can be used in industrial applications. has high value.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Novolak phenol m fat with a melting point of 75°C.

Rice husk powder 5002 with an apparent volume of 42 cc/201, hexamethylenetetramine 10 (1), valatoluenesulfonylhydrazone 102, magnesium oxide 102, calcium stearate 59, montan acid wax 42, and surfactant 42 were mixed together with methanol in a mixer. The mixture was then kneaded for 7 minutes using rolls heated to 80° C. to form a sheet, which was cooled and then crushed to obtain a molding material.

The disc flow rate of the molding material obtained was 132 degrees. −
The bowl lid obtained by compression molding has a specific gravity of 0.80,
Appearance: Good gloss and foaming ratio of 1.69.

The above-mentioned disk flow test conditions and bowl lid forming conditions are as follows. Note that the specific gravity was measured for a bowl lid that was molded using the minimum amount of sample required to obtain a bowl lid with a good appearance. We checked the bowl lid when molded by volume. Further, the foaming ratio was calculated from the specific gravity.

Mold temperature 140±3℃ Pressure 1500Kgf Pressure time
1 minute Sample amount 22 1l- 11) Molding conditions for bowl lid Mold temperature 160±3℃ Molding pressure 50 Kg/cal Pressure time 5 minutes Example 2 The same procedure as Example 1 was carried out using the formulation shown in Table 1. A molding material was obtained. The same test as in Example 1 was conducted using the obtained molding material. The results are shown in Table 2.

Comparative Examples 1 to 3 Molding materials were obtained in the same manner as in Example 1 using the formulations shown in Table 1. Comparative Example 1 is a case in which the cellulose base material and blowing agent are outside the scope of the present invention, Comparative Example 2 is a case in which only the blowing agent is within the scope of the present invention, and Comparative Example 3 is a case in which a cellulose base material and a blowing agent are within the scope of the present invention. This is a molding material in which only the material falls within the scope of the present invention. Note that all numbers for each component in Table 1 are 2.

The same test as in Example 1 was conducted using the obtained molding material. The results are shown in Table 2.

Table 1 (Note) Raw material characteristics Phenol novolac resin - Melting point 75℃ Rice husk powder -
The apparent volume is 42cc/201 wood powder-//
120cc720? Paratoluenesulfonylhydrazone - Decomposition temperature when coexisting in the molten state of phenolic resin 125-150°C Azodicarbonamide - Decomposition temperature 185-205°C as above (Note) The apparent volume of the mixed base material in Example 2 is 66cc /2
0? The apparent volume of the mixed base material of Comparative Example 3 is 57cc/20
y-15= Table 2 (Note) Appearance check criteria for bowl lid 1) Presence or absence of surface gloss ++) Presence or absence of bubbles, blisters, and gas defects on the surface 111) Based on the results of molding material filling properties and above From the molding materials obtained in Examples 1 and 2, low-foamed molded products with a specific gravity of 1.0 or less and good appearance were obtained, but from the molding materials obtained in Comparative Examples 1 and 3, the specific gravity was 1.0 or less. A value of 1.0 or less was not obtained, and a satisfactory appearance was not obtained due to insufficient filling, lack of gas, and lack of bubbles.

=16- 1 Display of the case 1982 Patent Application No. 120750 2 Name of the invention phenolic resin molding material for low foaming 3 Person making the amendment Related to the case Patent applicant Address 2-chome Nakanose-cho, Nobeoka City, Miyazaki Prefecture 5955, 8
Asahi Yokuzai Kogyo Co., Ltd. Representative Isamu Kawanami 4th generation Osamu Osamu Address: 5th floor, 7th floor, Tsuchiya Building, 6-4-5 Ginza, Chuo-ku, Tokyo 104 Column 8 of the detailed description of the invention in the subject specification Contents of the amendment (1) Change “l. θ or less” in the 6th line of the second page of the specification to “
Corrected to ``l, 2 or less''.

(2) In the second line from the bottom of the second page, “1. o J”
Corrected to 1.21.

(3) Change “02-1” in the 5th line of the 3rd page to “0.2”
~1.2” is corrected.

(4) "About 10 or less" in the 6th line of the 6th page of the same page is 1 about 1
Corrected to 2 or less.

(5) Change “1.0 or less” to “1.0” in the third line of page 11.
．． Corrected to 2 or less.

(6) 11. on page 17, line 6 from the bottom. "O or less" is corrected to "11.2 or less".

Claims (1)

[Claims] 1. Apparent volume is 30 to 80 cc for phenol resin.
/2Or of seed husk cellulose powder and phenolic resin 10
Decomposition temperature of 120 to 180°C in the presence of phenolic resin at a ratio of 40 to 400 parts by weight per 0 parts by weight
A phenolic resin molding material for low foaming, characterized in that the blowing agent is contained in a proportion of 0.2 to 5.0 parts by weight per 100 parts by weight of the total amount of phenolic resin and seed shell cellulose powder. 2. The molding material according to claim 1, wherein the seed husk cellulose powder is a powder of rice husk, peanut husk, buckwheat husk, or bean husk. 3 The blowing agent is a sulfonyl hydrazide or a hydrazone derived therefrom.Claim 1- The molding material according to the first @.