JPS6240491B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an advantageous method for producing products such as tatami flooring and its core material (hereinafter simply referred to as "products") having excellent quality using a binder containing terminal isocyanate groups. In general, commonly used products are manufactured by compressing and sewing materials such as rice straw, hard fiberboard, and foamed plastic, and the quality is determined by Japanese Industrial Standards JISA.
5901 and 5902. However, the following problems have been pointed out regarding the performance and manufacturing method of conventional tatami floors. (a) When foamed plastics such as styrene foam are subjected to partial loads for a long period of time, those areas become dented and are difficult to return to their original shape. (b) Tatami flooring is highly hygroscopic and has strong elasticity, making it difficult to transport as it has a large bulk density. (c) When it is flooded with rainwater, etc., it is difficult to dehydrate, rotting progresses, and it is easy to be infested with pests, which can lead to unfavorable sanitary results. (d) It is difficult to obtain good quality rice straw for manufacturing.
It is difficult to manufacture high-quality, uniform tatami floors. (E) During manufacturing, heat treatment and drying processes for insect repellent damage are complicated, resulting in low productivity. As a result of intensive research aimed at solving the above-mentioned performance and manufacturing problems, the inventors of the present invention added a terminal isocyanate group (-NCO) to the raw material of the product. The present invention was achieved based on the discovery that products with superior varieties can be obtained by using various binders. That is, the object of the present invention is to effectively produce tatami flooring and its core material using rice husks and wheat husks as main raw materials and a compound containing terminal isocyanate groups as a binder, and the object is achieved by the following method. be done. The method of the present invention uses rice husks and/or wheat husks as the main ingredients for the product, and for 100 parts by weight of the main ingredients, buckwheat husks, various types of wheat husks, rice straw, wheat straw, wood chips, 0 to 30 parts by weight of vegetable shells, scraps, chips such as fiber waste, and starches such as wheat flour and buckwheat flour, singly or in a mixture, preferably 5
For 100 parts by weight of raw materials mixed with ~20 parts by weight,
3 to 30 binders containing terminal isocyanate groups
It is characterized in that it is added in an amount of 4 to 15 parts by weight, preferably 4 to 15 parts by weight. The binder here refers to a polyisocyanate compound containing a terminal isocyanate group and/or a terminal isocyanate obtained by reacting the above isocyanate compound with a polyol having two or more active hydrogens in one molecule, preferably having a molecular weight of 60 or more. Preferably 0 to 50 parts by weight of various plasticizers such as dibutyl phthalate, dioctyl phthalate, chlorinated paraffin, trischloroethyl phosphate, tricresyl phosphate, etc., alone or in mixture, per 100 parts by weight of the group-containing urethane-modified prepolymer. is a mixture of 5 to 30 parts by weight, and these plasticizers not only lower the viscosity of the binder and improve the workability of mixing with raw materials, but also can impart appropriate softness and flexibility to the product. Other modifiers include flame retardant agents such as powdered borax, preservatives, fungicides such as fungicides, and insect repellents, as well as colorants and discoloration inhibitors to increase added value to products. Can be mixed. A tatami floor consists of an upper layer, an inner layer (called a core), and a lower layer.The upper and lower layers are made of rice straw;
Fiberboard and foamed plastic are used.
The product according to the present invention uses rice husk as the main material for the upper layer, inner layer, lower layer, or only the inner layer. Rice husk is characterized by being fibrous containing a large amount of inorganic matter, and having appropriate flexibility and water resistance. , has flame retardant properties, and is suitable for adjusting the texture of buckwheat husks and various wheat husks as auxiliary materials.Wheat flour and buckwheat flour are useful as binders for rice husks, and wood chips, fiber scraps, etc. is the bending of the product,
It is effective in imparting toughness against tension. If the amount of binder is less than 3 parts by weight with respect to 100 parts by weight of the raw materials mentioned above, it is too small to have a binder effect, and if it exceeds 30 parts by weight,
Not only does the product harden and lose its elasticity, but also its density increases, making it unsuitable for use. When using rice straw for the upper and lower layers, apply 1 to 20 parts by weight of a binder per 100 parts by weight of rice straw to the rice straw in both layers by spraying or kneading, heat, Pressure, molding and sewing processes yield products of even better quality. Among the molding conditions, the heating temperature is 50-150℃, preferably 80-120℃, and the pressure is 0.1-1Kg/
cm ² , preferably 0.1 to 0.5 Kg/cm ² . In this case, it is desirable to treat the surface of the molded plate of aluminum or the like used for pressurization with Teflon resin or silicone resin, or apply a similar type of mold release agent to make the pressure-formed plate easier to peel off. As described above, the polyol containing active hydrogen groups, which is a component of the binder, and the moisture contained in the raw materials of the product immediately cause a chemical reaction with the organic polyisocyanate compound, which is another component of the binder, and the urethane bond (-NHCOO -), urea bonds (-HNCONH-) are formed, and when there is a large amount of organic polyisocyanate compound or at relatively high temperatures, a secondary reaction occurs and allophanate bonds are formed.

[Formula] and viewer connection

[Formula] is formed and converted into a resin. In this process, when the raw materials are compression-molded, the binder components adhering to and impregnating them are bound together by strong adhesive force, and eventually polymerize and harden. Examples of the polyol of the present invention having two or more active hydrogens and preferably having a molecular weight of 60 or more include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, hexamethylene glycol, trimethylolpropane,
For addition polymerization of polyhydric alcohols such as glycerin, hexanetriol, pentaerythritol, and sorbitol, and amine compounds such as diisopropanolaniline and triisopropanolamine alone and/or in mixtures with ethylene oxide, propylene oxide, butylene oxide, etc. The polyether polyols and polyamines thus obtained, as well as the above polyhydric alcohols alone or in mixtures, and saturated fatty acids such as adipic acid, pimelic acid, azelaic acid, and sebacic acid, and unsaturated fatty acids such as maleic acid, fumaric acid, and dimer acid. and various polyols such as polyester polyols obtained either singly or in combination with aromatic fatty acids such as phthalic acid and terephthalic acid or their anhydrides. Examples of the polyisocyanate compounds used include polyisocyanate compounds such as tolylene diisocyanate, crude tolylene diisocyanate, diphenylmethane diisocyanate, liquefied diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, etc. alone or in mixtures, and the above polyisocyanates. Less than 1 mol of the polyol having active hydrogen is added per 1 mol, that is, a polyol containing an excess of isocyanate is used. The NCO content of this prepolymer containing terminal isocyanate groups is 8 to 35%, preferably 10 to 25%. When it does not contain any polyol, it does not have a urethane bond, but when it contains a polyol, it becomes a urethane-modified polyisocyanate compound that has a urethane bond. That is, the main component of the binder is an isocyanate compound or a urethane-modified isocyanate compound, but this urethane-modified isocyanate compound can also be prepared at the same time or immediately before mixing with the raw materials (some unreacted active hydrogen compounds and excess (can also be used in a mixed state with polyisocyanate compounds). When using a binder, it is possible to dissolve it in a small amount of a solvent such as methyl ethyl ketone, ethyl acetate, or 1,1,1-trichloroethane as an auxiliary means of uniformly mixing it with the raw materials, but there is a risk of ignition. However, as mentioned above, it is more effective to mix a plasticizer, and the amount used is 0 to 50 parts by weight per 100 parts by weight of the main binder material.
It is best to mix parts by weight. In addition, in order to increase the added value of the binder, it is also effective to previously contain flame retardant agents, fungicides, insecticides, colorants, discoloration inhibitors, and the like. Thus, by using the binder of the present invention, it is possible to economically produce products of excellent quality without adjusting the moisture content of raw materials and without causing health and hygiene problems. can. As is clear from the above explanation, according to the present invention, (a) rice husks, etc., which have almost no use can be effectively activated, and therefore the raw material cost is low; (b) the present invention Products manufactured by the method described above have appropriate heat retention, moisture absorption, and air permeability, and (c) have superior durability compared to conventional products, and are also advantageous in terms of hygiene. (d) Manufacture is relatively easy and mass production of products of a certain standard is possible. Next, the present invention will be explained by examples. Various physical property measurements in the examples were conducted based on JISA5902 tatami flooring. Example 1 Binder A [polyphenylmethane polyisocyanate (NCO-containing A reaction product consisting of 250 parts by weight of polypropylene glycol (molecular weight 2000), 200 parts by weight of dioctyl phthalate, 10 parts by weight of NCO content 15.3%, viscosity 700 cps/25°C] were mixed and stirred. Next, this is molded into a single layer core material for tatami flooring as shown in Figure 1 under molding conditions of 0.2 to 0.5 kg/cm ² , 100°C, and 10 minutes using a pressurized hot plate whose surface has been treated with a mold release agent. did. Example 2 100 parts by weight of a mixture of rice husks and buckwheat husks (mixing ratio 100/20 parts, water content 3-4%) as a raw material was mixed with binder B [Coronate L (manufactured by Nippon Polyurethane Industries Co., Ltd., tolylene diisocyanate). and trimethylolpropane) and ethyl acetate and 1.1.
It consists of a 60% mixed solution of 1-trichloroethane. ] was used to form a core material for a tatami floor in one layer in the same manner as in Example 1. Example 3 20 parts by weight of binder C [a mixture consisting of 300 parts by weight of polyphenylmethane polyisocyanate (NCO content 26.5%) and 100 parts by weight of trischloroethyl phosphate] was added to 100 parts by weight of the rice husks used in Example 1. The core material for tatami flooring is made from
The upper layer of the tatami bed made of 100 parts by weight of rice straw (moisture content 6 to 10%) and 20 parts by weight of binder C was molded to form the two-layer tatami bed shown in FIG. Example 4 Mixture of rice husks and buckwheat husks (same as Example 2)
The core material for the tatami floor is made from 100 parts by weight of binder C added to 20 parts by weight, and the upper and lower layers of the tatami floor are made from 100 parts by weight of rice straw (same as in Example 3) plus 20 parts by weight of binder C. The three-layer tatami floor shown in Figure 3 was created. Table 1 shows examples of formulations for each of the above-mentioned examples for making each material for tatami flooring, and Table 2 shows the physical properties thereof.

【table】

According to [Table].

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the core material (single layer) of the tatami floor according to the present invention, and FIGS. 2 and 3 show embodiment examples of the tatami floor (in the case of two and three layers) according to the present invention. are shown respectively.

Claims (1)

[Claims] 1 Rice husk and/or wheat husk 100 as main material
A material mixed with 0 to 30 parts by weight of vegetable shells, scraps, chips such as wood chips, fiber chips, buckwheat hulls, rice straw, etc. alone or in a mixture based on the weight part
Terminal consisting of an organic polyisocyanate compound having two or more isocyanate groups in one molecule, or a reaction product of the above organic polyisocyanate and a polyol having two or more active hydrogens in one molecule, per 100 parts by weight. A tatami floor or the like is produced by mixing 3 to 30 parts by weight of a mixed liquid consisting of 100 parts by weight of an isocyanate group-containing prepolymer and 0 to 80 parts by weight of a plasticizer, and heating, pressing, and forming the mixture on a metal plate. Manufacturing method of core material.