JPH04359957A - Molding material and production of molded article - Google Patents

Abstract

PURPOSE:To provide a molding material which generates very little gas during and after the molding and to produce a molded article free of defect due to the gas. CONSTITUTION:A binder consisting of a mixture of a novolac phenol resin powder with hexamethylenetetramine is mixed with an inorg. aggregate consisting of a mixture of fly ash with a small amt. of boric acid, thus giving a molding material which generates very little gas, e.g. an amine or formalin, during and after the molding. The material is thermally press-molded in a metal mold into an article free of defect due to the gas and excellent in strengths.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding material that releases less gas during molding or after construction and produces molded products with fewer gas defects, and a method for manufacturing molded products using the same.

0002

[Prior Art] Noncombustible materials and exterior materials with excellent flame retardancy and water resistance use a mixture of novolac type phenol resin and hexamethylenetetramine as a binder, and volcanic debris or volcanic ash as an inorganic aggregate. It is known that this is thermoset and molded.

0003

[Problems to be Solved by the Invention] However, the above-mentioned molding materials have the problem of emitting odorous gases such as ammonia and formaldehyde during heat curing, and furthermore, the molded products are hardened due to the release of gases. The disadvantage was that gas defects were likely to occur.

0004

[Means for Solving the Problems] The inventors of the present invention have made extensive studies in view of the above-mentioned circumstances, and have found that when a specific compound is added to a molding material, gas generation during molding due to heating and curing is significantly reduced. It was discovered that a molded product with extremely few gas defects can be obtained, and the present invention was completed.

That is, the present invention provides a molding material comprising a novolac type phenolic resin, hexamethylenetetramine, boric acid and/or iron oxide, and a method for producing a molded article by heating and curing the same.

[0006] As the novolac type phenolic resin according to the present invention, any known and commonly used ones can be used. Among these, high-orthophenol novolac type phenolic resins are preferred over conventional novolac type phenolic resins because of their faster curing speed.

[0007] Novolak type phenolic resins can be easily produced by, for example, reacting a formaldehyde supplying substance and phenols in the presence of a catalyst if necessary in a molar ratio of 0.7 to 1.0. can be obtained.

[0008] As the phenols used in the present invention, any known and commonly used phenols can be used, and examples thereof include phenol, bisphenols such as bisphenol F, bisphenol A, and bisphenol AF, cresol, and Phenol.
- Alkyl-substituted phenols such as tertiary butylphenol, halogenophenols such as bromophenol, aromatic hydrocarbons containing two or more phenolic hydroxyl groups such as resorcinol, 1-naphthol, 2-naphthol, 1,6-dihydroxynaphthalene , 2,7-dihydroxynaphthalene and other naphthols. These phenols may be used not only alone, but also as a mixture of two or more of these compounds.

[0009] As the formaldehyde supplying substance, any known material can be used, and for example, formaldehyde aqueous solution and paraformaldehyde can be used. Examples of the catalyst include acid catalysts such as oxalic acid, hydrochloric acid, and sulfuric acid, and metal salt catalysts such as zinc acetate and manganese borate. When the metal salt catalyst is used, a high orthophenol novolac type phenol resin can be obtained.

[0010] In producing the novolac type phenolic resin, furfural, urea, melamine, acetoguanamine, benzoguanamine, etc. may be used in combination with the phenol, if necessary.

The above reaction may be carried out in the presence of an organic solvent, or an organic solvent may be added to the obtained reaction product. The reaction may be carried out in a batch kettle or in a tubular reactor with static mixing elements.

[0012] Usually, the novolac type phenolic resin used in the present invention is in powder form. When the novolac type phenol resin is in the form of an aqueous solution, an aqueous dispersion, or an organic solvent solution, it is preferable to remove the solvent, dry it, and grind it before use. For removing the solvent and drying, for example, a thin film evaporator or a spray dryer can be used.

In the present invention, the mixing ratio of the novolac type phenol resin and hexamethylenetetramine is not particularly limited, but usually 5 to 25 parts by weight of hexamethylenetetramine per 100 parts by weight of the solid content of the novolak type phenol resin. It is.

In the present invention, boric acid and/or iron oxide are important components that trap gas. The amount of boric acid and/or iron oxide used is not particularly limited, but
Usually 1 per 100 parts by weight of hexamethylenetetramine
It is 0 to 100 parts by weight.

The molding material of the present invention may contain a novolac type phenol resin, hexamethylenetetramine, boric acid and/or iron oxide as essential components, but if necessary, other thermosetting resin compositions may be added. materials, inorganic aggregates, fibrous base materials, etc. may be used in combination.

Examples of thermosetting resin compositions that can be used in combination with novolac type phenol resin and hexamethylenetetramine include resol type phenol resin, melamine-formaldehyde resin, and urea-formaldehyde resin.

[0017] Examples of the inorganic aggregate include magnesia, alumina, calcium carbonate, magnesium carbonate, calcium oxide, volcanic ash, volcanic rubble, fly ash, etc. Volcanic ash, volcanic rubble, and fly ash are preferred from the economic point of view. .

[0018] The particle size of the inorganic aggregate is not particularly limited, but it is usually preferably about 0.001 to 6 mm. By using a combination of inorganic aggregates with different particle sizes and adjusting the proportions as necessary, it is possible to obtain a lightweight and strong molded product.

Examples of the fibrous base material include glass fiber,
Examples include inorganic fiber base materials such as carbon fiber and silicon carbide fiber, phenolic resin fibers, aramid resin fibers, polyarylene sulfide resin fibers, and nylon fibers, but the resulting molded products have excellent strength and are also economical. Glass fiber is preferred because of its superior properties.

[0020] The form of the fibrous base material is not particularly limited, and examples include chopped strands, chopped mats, chopped cloth, roving, roving cloth,
Examples include nonwoven fabrics.

The fibrous base material can be used as it is, but it can be coated with or impregnated with a phenol resin prepared by mixing hexamethylenetetramine with a novolac type phenol resin and/or resol type phenol resin as necessary. It is preferable to use a staged (semi-cured) or C-staged (completely cured) fiber base material because this improves the strength of the final molded product.

[0022] The molding material of the present invention may further contain a silane coupling agent, a flame retardant, a plasticizer, a mold release agent,
Additives such as colorants may be added. The molding material of the present invention is produced by uniformly kneading a novolac type phenolic resin, hexamethylenetetramine, boric acid and/or iron oxide as raw materials, filling a mold of a predetermined shape, and thermoforming. It can be easily obtained by curing.

[0023] The conditions for thermoforming are not particularly limited, but are usually 130 to 250°C for 3 to 60 minutes. The pressure depends on the density of the target molded product, but is usually 10
~100 kg/cm2.

Next, an example of a method for manufacturing a molded article using the molding material of the present invention will be described. (1) First, a mixture of novolac type phenolic resin, hexamethylenetetramine, inorganic aggregate, boric acid and/or iron oxide is sprinkled into the mold. (2) Next, place a B-type glass cloth impregnated with novolac type phenol resin on top of this, and further add novolac type phenol resin and hexamethylene to the inorganic aggregate moistened with water as necessary. Spray a mixture of tetramine and boric acid and/or iron oxide. (3) A glass cloth impregnated with a phenol resin in a B state is placed on top of the above layer, and the mixture used in (1) is further sprinkled thereon. (4) The sandwich-like product obtained in (3) above is hot-pressed to a predetermined thickness.

[0025]

EXAMPLES Next, the present invention will be explained using examples, in which "parts" and "%" represent parts by weight, unless otherwise specified. Example 1 Novolac type phenolic resin powder [melting point 80°C (capillary method), gelation time 65 seconds (on 150°C cure plate)
, flow rate 35mm (125℃, on a 30 degree inclined glass plate)
] and 15 parts of hexamethylenetetramine were mixed to prepare a binder.

0.01~0.1mm fly ash 9
2 parts of boric acid (industrial grade 2) was added to 8 parts to prepare a boric acid-containing inorganic aggregate. A mixture of 100 parts of the above-mentioned inorganic aggregate containing boric acid and 15 parts of the above-mentioned binder (hereinafter referred to as mixture A) was uniformly spread at 1.5 kg/m2 on a stainless steel plate.

Next, glass cloth EP11E (JIS
R3414 (weight: 65 g/m2) was mixed into a methanol solution of a mixture of novolak type phenolic resin and resol type phenolic resin at a solid content weight ratio of 1/1 [resin solid content: 55 g/m2).
%, viscosity 80 cps/25°C], impregnated, squeezed out excess resin with a roll, and dried in a hot air circulation drying oven for 10 minutes.
It was dried at 0° C. for 3 minutes to obtain 95 g/m 2 of impregnated B-cured glass cloth prepreg, which was placed on top of what had already been sprayed.

[0028] On top of this, the above mixture A is prepared once again, 5 parts of water is added to 100 parts of this mixture, and the mixture is moistened. 100 parts of a 1/1 weight ratio mixture of volcanic rubble having a diameter of 3 to 5 mm was added, mixed well, and uniformly spread on the 5.4 kg/m2 prepreg.

On top of this, the same prepreg as described above is further placed, and on top of this prepreg, 100 parts of the same mixture A as above is evenly spread at 1.5 kg/m2 to form a lower layer divided by the two prepregs. The weight ratio of middle layer/upper layer was set to 1/3/1 to obtain a sandwich-like product.

[0030] Pressure was applied to the sandwich-like product thus produced until it had a thickness of 10 mm, and the product was molded at a temperature of 160° C. for 10 minutes. Thereafter, it was cured at 120° C. for 16 hours to obtain a molded product having a thickness of 10 mm and a bulk specific gravity of 0.85. This molded article had extremely few gas defects.

[0031] The amount of each gas generated during molding of the sandwich-like product and the strength of the molded product obtained were measured, and the values are shown in Table 1. The gas amount was measured by directly measuring the gas generated from the side of the molding material 2 minutes after the start of molding using a Kitagawa gas detection tube (unit: ppm). Amine gas was measured for the amount of methylamine generated.

The normal bending strength of the molded product was measured using an Autograph manufactured by Shimadzu Corporation under conditions of a width of 25 mm, a span of 150 mm, and a head loading rate of 10 mm/min. The water flexural strength was measured by immersing the product in water at room temperature (25° C.) for one day and night (24 hours) while it remained wet, and otherwise under the same conditions as the normal flexural strength. The results are shown in Table 1. Example 2 A molded article was produced in the same manner as in Example 1, except that the same amount of Noben No. 10 (iron oxide manufactured by Ikegai Co., Ltd.) was used instead of boric acid. Regarding this molded article, the amount of each gas generated and the strength of the molded article were measured in the same manner as in Example 1. Table 1 shows the results.
It was shown to. The thickness of the obtained molded product was 10 mm, and the bulk specific gravity was 0.85. This molded article had extremely few gas defects. Example 3 A molded product was produced in the same manner as in Example 1, except that the same amount of a mixture of boric acid/iron oxide (weight ratio) of 1/1 (weight ratio) was used instead of boric acid. Regarding this molded article, the amount of each gas generated and the strength of the molded article were measured in the same manner as in Example 1. The results are shown in Table 1. In addition, the thickness of the obtained molded product is 10 mm,
The bulk specific gravity was 0.85. This molded article had extremely few gas defects. Comparative Example 1 A molded article was produced in the same manner as in Example 1 except that 7 parts of boric acid was replaced with fly ash and no boric acid or iron oxide was used. Regarding this molded article, the amount of each gas generated and the strength of the molded article were measured in the same manner as in Example 1. The results are shown in Table 1. The thickness of the obtained molded product was 10 mm, and the bulk specific gravity was 0.85.

[0033]

[Table 1]

As can be seen from Table 1, it is clear that molded articles using the molding material of the present invention generate significantly less odor.

[0035]

Effects of the Invention: Since the molding material of the present invention uses boric acid and/or iron oxide, there is extremely little release of gas such as amine odor or formalin odor during molding or after construction, resulting in molding with fewer gas defects. You can get the goods.

Claims (6)

[Claims] 1. A molding material comprising a novolac type phenolic resin, hexamethylenetetramine, boric acid and/or iron oxide. 2. The molding material according to claim 1, further comprising an inorganic aggregate. 3. The molding material according to claim 2, wherein the inorganic aggregate is volcanic rubble and/or volcanic ash. 4. The molding material according to claim 1, further comprising a fibrous base material. 5. The molding material according to claim 1, wherein the fibrous base material further contains a fibrous base material that has been previously treated with a phenolic resin. 6. A method for producing a molded article, which comprises heating and curing the molding material according to claim 1.