JPS6320857B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention relates to a phenolic resin molding material for low-foamed products,
More specifically, tableware, souvenirs, decorations,
Specific gravity 0.75, which can be used as a substitute for wooden products such as toys.
~1.0 low foam molded products, especially low foam molded products with complex shapes that are difficult to foam mold.
The present invention relates to a phenolic resin molding material that provides large-sized low-foaming molded products or thick low-foaming molded products. Conventional technology In the past, food items, souvenirs, decorations, toys, etc. were mainly molded using wood, but in recent years molding of thermoplastic resin and thermosetting resin has been used as an alternative to these wood products. Molded products using this material are commercially available. However, molded products made of resin that have the feel and functionality of wood have not yet been obtained. For example, when molded products made from thermoplastic resin molding materials are immersed in hot water, they become soft and easily deformed, and when used as tableware, when high-temperature contents are placed in them, they become too hot to hold in the hand. It has drawbacks such as: On the other hand, molded products obtained from thermosetting resin molding materials, such as phenolic resin molding materials, do not soften or deform even if hot water is poured into them, but if hot contents are poured into the container, the container becomes hot. The disadvantage of not being able to hold it in your hands is inevitable. On the other hand, low-foaming phenolic resin moldings with a specific gravity of 0.75 to 1.0 do not soften even when hot water is poured into them, and the surface temperature of the container does not become high. It is manufactured by combining phenolic resin with a hardening agent such as hexamethylenetetramine, a foaming agent that decomposes when heated and generates a large amount of gas, and a divalent metal oxide, and then heat-foaming the mixture. -24266). However, although this low-foaming phenolic resin molding does not pose a problem when used to make tableware of small and relatively simple shapes, such as soup bowls and flat plates, it is difficult to use the low-foaming phenolic resin moldings when making tableware of complex shapes, large size or thick walls, etc. For example, wavy confectionery bowls, salad bowls,
When used to make waist-high confectionery plates, etc., nests are likely to form inside the plate, causing phenomena such as surface peeling and end portion loss, which significantly reduces the product value. Therefore, there has been a demand for a synthetic resin molding material that has a specific gravity comparable to that of wood, exhibits good heat insulation properties, and is suitable for manufacturing tableware with complex shapes, large size, or thick walls. was. In order to meet these demands, the present inventors have conducted various studies on improving the physical properties of phenolic resin molding materials, and have found that the fluidity of phenolic resin before and after foaming is related to the vegetable base material filled into it. We obtained the knowledge that this significantly affects the state of closed cell formation during foaming, and based on this, we added 40 to 400 parts by weight of seed husk cellulose powder and the necessary amount of blowing agent to 100 parts by weight of phenolic resin. proposed a low-foaming phenolic resin molding material containing (Japanese Unexamined Patent Publication No. 11339/1983). However, with this molding material, things that can be relatively easily molded, such as soup bowls and flat plates, have a good appearance and sufficient strength to withstand normal use by compression molding, and have a specific gravity of 1.0 or less. However, when it comes to molded products with complex shapes that are difficult to mold, such as wavy confectionery bowls, cavities are likely to form inside the molded products, which deteriorates strength and appearance. There was no way I could escape the drawback of being damaged. Problems to be Solved by the Invention The purpose of the present invention is to solve these problems,
Low-foam molded products with a specific gravity of 0.75 to 1.0 can be used as substitutes for wood products, especially low-foam molded products with complex shapes that are difficult to foam mold, large low-foam molded products, or thick-walled low-foam molded products. It is an object of the present invention to provide a phenolic resin molding material that can be easily foam-molded into foam molded articles. Means for Solving the Problems The present inventors first conducted various studies on the causes of cavities forming inside foam molded products, and found that the fluidity of the molding material is important for preventing the destruction of the foam membrane during foam molding. Although this is a requirement, we have also found that by increasing the curing speed appropriately, the occurrence of cavities inside the molded product can be reduced. Therefore, the present inventors conducted further research and found that the ratio of ortho bonds and para bonds present in the molecules constituting the resin was 2.0:1 or 2.0:1.
A novolac-type phenolic resin rich in ortho bonds in the range of 10.0:1 has the desired curing speed, and seed shell cellulose powder or purified cellulose is added to this as a filling base material that provides fluidity and viscoelasticity. Furthermore, the inventors have discovered that a molding material whose basic composition is a mixture of blowing agents having a decomposition temperature within a specific range in a predetermined ratio can be suitable for the above purpose, and based on this knowledge, the present invention has been completed. It came to this. That is, the present invention provides (A) 100 parts by weight of a novolak-type phenolic resin rich in ortho bonds, in which the ratio of ortho bonds to para bonds present in the molecules constituting the resin, that is, the o/p ratio, is 2.0 to 10.0. On the other hand,
(B) At least one fibrous base material component selected from seed shell cellulose powder and purified cellulose10
The present invention provides a phenolic resin molding material for low-foam objects, characterized in that it contains 0.5 to 5.0 parts by weight of a blowing agent having a decomposition temperature of 100 to 180° C. and (C) 0.5 to 5.0 parts by weight of a blowing agent having a decomposition temperature of 100 to 180°C. In the molding material of the present invention, the o/p ratio of the novolak type phenolic resin as component (A) is 2.0 to 2.0.
10.0, preferably in the range of 2.5 to 5.5. If a material with this ratio smaller than 2.0 is used, the curing speed of the resulting molding material will be slow, which will result in cavities inside the molded product and defects such as surface peeling and end part loss when producing products that are highly difficult to mold. Consequently, a product with sufficient strength and good appearance cannot be obtained. On the other hand, if a material with a ratio greater than 10.0 is used, the resulting molding material will harden too quickly, resulting in decreased fluidity and difficulty in preforming, as well as air bubbles and scratches at the top of the product. This may cause The O/P ratio of novolak type phenolic resin is determined from the infrared absorption spectrum (hereinafter abbreviated as IR spectrum).
Characteristic absorption of out-of-plane bending vibration of the 1,2-substituted substance near 770-735 Kaiser (characteristic absorption of ortho bond) and 1,4- around 840-810 Kaiser.
It expresses the ratio of the strength of the characteristic absorption of out-of-plane bending vibration (characteristic absorption of para bond) of the substituted body, and is determined by the following measurement method. That is, about 1 mg of novolac-type phenolic resin rich in ortho bonds is mixed with about 200 mg of dried potassium bromide powder for IR spectra, and the transmittance of the characteristic absorption of ortho bonds in the IR spectrum is 35±.
Adjust the thickness of the tablet to 5%. From the measured IR spectrum, the o/p ratio is determined according to the following formula: Ortho bond/para bond = log Ioa/Ia/log Iob/Ib. However, Ioa, Ia, Iob, and Ib are transmittances determined based on the baseline of the method shown in the drawings. The novolac type phenolic resin used in the present invention has an O/P ratio in the range of 2.0 to 10.0, for example, 0.67 to 0.82 mol of aldehydes such as formaldehyde and acetaldehyde per 1 mol of phenols such as phenol, resorcinol, and m-cresol. can be obtained by heating and reacting in the presence of a catalyst and dehydrating the product under suction. As the catalyst in this case, divalent metal oxides, chlorides, and salts with weak acids, such as magnesium oxide, calcium oxide, zinc chloride, and calcium acetate, are used. These may be used alone or in combination of two or more. Next, as the fibrous base material of component (B) in the present invention, seed shell cellulose or purified cellulose is used. Suitable examples of this seed husk cellulose include powders such as rice husks, peanut husks, buckwheat husks, and bean husks; examples of refined cellulose include wood pulp,
Linter pulp and the like are suitable. Note that purified cellulose as used in the present invention is obtained by mechanically and chemically treating materials containing cellulose. For example, wood pulp, which is a type of purified cellulose, is obtained by processing wood chips. Cellulose is extracted by boiling in the presence of acid, mechanically destroying the lignin adhering to cellulose cells in the wood, and chemically eluting it, followed by alkaline treatment, bleaching, and making it into sheets using a paper machine. It is obtained by drying and pulverizing it. This seed shell cellulose plays the role of imparting fluidity to the molding material at low temperatures of about 120° C. or lower, thereby making it possible to easily preform the molding material. Further, since purified cellulose is uniformly dispersed in the phenolic resin and partially dissolved, it improves the viscoelasticity of the molding material and strengthens the cell membrane during molding. Such effects cannot be obtained with unrefined cellulose such as wood flour. It is advantageous to use seed husk cellulose and purified cellulose together because a synergistic effect can be obtained between the two. This fibrous base material is preferably used in powder form. The blending amount is 100% of the phenolic resin.
Based on parts by weight, a range of 10 to 55 parts by weight is used. If this amount is less than 10 parts by weight, the viscoelasticity of the molding material during hot melting will be low, and as a result, the foam membrane will collapse during the foaming process, which will easily cause cavities due to open cells inside the resulting molded product, resulting in poor molding. I can't get a body. On the other hand, if it exceeds 55 parts by weight, the fluidity of the molding material during hot melting becomes low, making preforming difficult and causing poor filling, making it impossible to obtain a good molded body. The blowing agent used as component (C) in the present invention must have a decomposition temperature of 100 to 180° C. when mixed with components (A) and (B). Preferred examples of such compounds include dinitrosopentamethylenetetramine, p-toluenesulfonylacetone hydrazone, and p-toluenesulfonylhydrazide. These foaming agents are usually used alone, but two or more types can also be used in combination to adjust the timing of foaming. The decomposition temperature in the present invention is the decomposition temperature when the blowing agent coexists with the above-mentioned components (A) and (B), and is generally the decomposition temperature of the blowing agent alone as described in literature. It is normal to be lower. The amount of the blowing agent used is in the range of 0.5 to 50 parts by weight per 100 parts by weight of the phenolic resin. This suitable amount varies depending on the specific gravity of the low foam to be obtained, but is usually selected within the range of 1.0 to 3.0 parts by weight. If this amount is less than 0.5 parts by weight, a molded product with a specific gravity of 0.75 to 1.0 cannot be obtained, and
If it exceeds 5.0 parts by weight, open cells will be formed inside or on the surface of the molded product, resulting in a molded product with low strength and poor appearance. To prepare the phenolic resin molding material for low-foamed objects of the present invention, 100 parts by weight of a novolak type phenolic resin having an o/p ratio of 2.0 to 10.0 is added to a fibrous base consisting of seed shell cellulose powder, purified cellulose, or both. 10 to 55 parts by weight of the material and the (A) component and
Decomposition temperature in coexistence with component (B) is 100-180℃
0.5 to 5.0 parts by weight of a blowing agent are added, and if necessary, appropriate amounts of additives such as a curing agent, curing catalyst, mold release agent, and coloring agent are added, and then mixed in a mixer with an appropriate amount of solvent. Next, the resulting mixture is kneaded with heated rolls, drawn out into a sheet, and granulated or pulverized to an appropriate particle size to obtain the desired phenolic resin molding material for low-foaming products. The predetermined amount of the molding material thus obtained is approx.
By putting it into a mold heated to 120-150℃ and compression molding for about 5-15 minutes after preforming,
For example, complex molded bodies such as wavy confectionery bowls can be obtained. Effects of the Invention The molding material of the present invention exhibits good fluidity in a low temperature range of about 150°C or less, and easily foams in this temperature range, forming uniformly dispersed fine closed cells with a strong cell membrane. Therefore, it is easy to preform, and it is possible to easily mold complex shaped molded products, large molded products, or thick molded products that are relatively difficult to mold. Further, since there are no undesirable phenomena such as the formation of cavities inside the molded product, surface peeling, or loss of end portions, it is possible to obtain a molded product with sufficient strength and an excellent appearance. Further, since purified cellulose does not contain oil or impurities, its use has the advantage of providing a product with excellent paint adhesion. Furthermore, the molded product obtained from the molding material of the present invention has a specific gravity in the range of 0.75 to 1.0, floats on water, is lightweight, has good insulation properties, and has a wood texture, so it can be used for tableware, commemorative items, etc. It is suitable as a manufacturing material for wood products such as goods, decorations, and toys. EXAMPLES Next, the present invention will be explained in more detail with reference to Examples. Example 1 High ortho type novolac type phenolic resin (o/p ratio = 4.0) 700g Rice husk powder 100g Wood pulp 200g Dinitrosopentamethylenetetramine 8g Hexamethylenetetramine 90g Magnesium oxide 20g Stearic acid 14g The above mixture was mixed with methanol. Next, this mixture was kneaded for about 12 minutes using rolls heated to 80°C, and the resulting sheet was cooled and pulverized to obtain a phenolic resin molding material. The disc flow of the obtained molding material was measured according to JISK6911 under the following conditions, and the result was 110 mm. Conditions: Mold temperature 140±3℃ Molding pressure 1500Kg Pressure time 1 minute Sample amount 2g Using the obtained molding material 530g, mold temperature 120
Compression molding was performed under the conditions of ~140°C, molding pressure of 150 Kg/cm ² , and pressurization time of 7 minutes, and a wavy confectionery bowl could be formed. The obtained molded product had a specific gravity of 0.97 and a woody texture, and the surface of the molded product was glossy and showed no defects such as scratches, cracks, or bubbles, and there were no cavities in the cross section of the molded product. No open air bubbles or the like were observed, and the internal cell structure was uniform and dense, with sufficient strength, good appearance, and excellent paint adhesion. Examples 2 to 6 Phenol resin molding materials were obtained in the same manner as in Example 1 using the formulations shown in Table 1. Table 2 shows the disc flow of each of the molding materials obtained. Using 530 g of the obtained molding material, a wavy confectionery pot could be molded in the same manner as in Example 1.
Table 2 shows the specific gravity and appearance of the molded product obtained. Comparative Examples 1 to 5 Phenol resin molding materials were obtained in the same manner as in Example 1 using the formulations shown in Table 1. Table 2 shows the disc flow of each of the molding materials obtained. Using 530 g of the obtained molding material, a wavy confectionery pot could be molded in the same manner as in Example 1.
Table 2 shows the specific gravity and appearance of the molded product obtained.

【table】

【table】 [Brief explanation of the drawing]

The drawing is an example of an infrared absorption spectrum diagram for explaining the method for calculating the O/P ratio of the novolak type phenolic resin used in the present invention.

Claims (1)

[Scope of Claims] 1 (A) 100 parts by weight of a novolac-type phenolic resin rich in ortho bonds, in which the ratio of ortho bonds to para bonds present in the molecules constituting the resin is in the range of 2.0:1 to 10.0:1. (B) at least one selected from seed husk cellulose and purified cellulose;
10 to 55 parts by weight of the fibrous base material component of seeds and 100 to 180 parts by weight of (C)
A phenolic resin molding material for low-foamed objects, characterized in that it contains 0.5 to 5.0 parts by weight of a blowing agent having a decomposition temperature of °C. 2. The molding material according to claim 1, wherein the seed husk cellulose is at least one selected from rice husk, peanut husk, buckwheat husk, and bean husk. 3. The molding material according to claim 1, wherein the purified cellulose is at least one selected from wood pulp and linter pulp. 4. Claims 1, 2, or 3, wherein the blowing agent is at least one selected from dinitrosopentamethylenetetramine, p-toluenesulfonylacetone hydrazone, and p-toluenesulfonyl hydrazide. molding material.