JP3502149B2 - Hygroscopic polyurethane foam and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane foam having a high hygroscopic property and a method for producing the same, and more particularly to a polyurethane foam having a high hygroscopic property suitable for use as an interior material for furniture such as chairs and sofas and seats for vehicles. And a method for producing the same.

[0002]

2. Description of the Related Art In recent years, the high-grade interior of furniture, vehicles and the like has been fulfilled in accordance with the improvement of taste and demand of people who use them, and it has reached a satisfactory level. On the other hand, as demands for improving comfort such as soundproofing and heat insulation in the room become stronger, higher airtightness is also required, which is a major cause of increase in room temperature and generation of dew condensation.

However, under the present circumstances, little consideration is given to hygroscopicity, which is a decisive factor in improving these causes.

In particular, chairs and vehicle seats used indoors usually use a considerable amount of polyurethane foam in order to improve soundproofing, heat insulation, shock absorption and cushioning, and absorb moisture generated in the room. Or
It would be convenient if it could be effectively used as a medium for releasing moisture.

Polyurethane foam is essentially hygroscopic because it is made of synthetic resin. Therefore, some proposals have been made to develop a polyurethane foam having a high hygroscopic property suitable for the above-mentioned applications.

For example, Japanese Patent Application Laid-Open No. 58-175652 proposes a method of needle-punching ultrafine fibers having moisture absorbing / releasing properties inside a polyurethane foam sheet to obtain a flexible composite material. However, since this method is performed after molding the molded product, it tends to deteriorate the cushioning property and air permeability of the foam.In addition, such a post-treatment complicates the manufacturing process, and the surface layer of the molded product is treated. Therefore, it is difficult to give an effect. On the other hand, a method of mixing leather powder or gelatin powder into a urethane resin when producing a polyurethane foam has been proposed, but when leather powder is mixed into the urethane resin, the particle size of the leather powder is large. The mixed resin material has little lubricity and deteriorates the fluidity of the resin. Therefore, the extrusion resistance becomes large during molding, which hinders smooth extrusion.

Further, there is a problem that it takes time to uniformly knead the resin and the powder. When using gelatin,
Even if the gelatin powder has a small particle size, it is easily pulverized by pulverization, so that agglomeration easily occurs, which causes uneven distribution of the powder in the resin, which causes molding distortion and deviation of the molded product. There is.

An object of the present invention is to solve the above-mentioned problems and to provide a polyurethane foam having an excellent hygroscopic function not found in conventional polyurethane foam sheets and a method for producing the same.

[0009]

Means for Solving the Problems The present invention microspheres sericin bubble film and the skeleton of the polyurethane foam in the first
It is a polyurethane foam which is dispersed in the form of powder and has excellent hygroscopicity . Secondly, when a polyurethane foam is produced by reacting a composition containing a polyol, a polyisocyanate, a catalyst and a foaming agent, the polyol 10
0 parts by weight per 0.01 to 50 parts by weight of sericin and microspheres
Absorption characterized by reacting in the form of powder
A method for producing a polyurethane foam having excellent properties .

The sericin used in the present invention has an average particle size of 20.
It is a spherical powder having a particle size of not more than 10 μm , particularly preferably a maximum particle size of not more than 10 μm and an average particle size of about 5 μm. These sericins are usually obtained from silk scouring liquids and have an average molecular weight of 60.
It has 0 to 40,000.

Polyurethane foam forms a cell surface
The continuity of the cellular membrane and the polyurethane connecting them
Although consisting of a skeleton of phase, poly urethane foam of the present invention are those having a structure in which sericin described above are dispersed into the bubble membrane portion and the backbone of the polyurethane foam, co sericin during polyurethane foam production reaction It is manufactured by

As the raw material compound used for producing the polyurethane foam and the production conditions for the foam, conventionally known raw material compounds and conditions can be appropriately adopted.

Polyurethane foams, raw materials for production, require a polyol, a polyisocyanate, a catalyst and a foaming agent, and usually further contain a foam stabilizer and other additives.

The polyol used in the method of the present invention is a compound having two or more terminal hydroxyl groups, and in polyether polyols, polyester polyols, and polyether polyester polyols and polyols which are copolymers of these two kinds. Polyols such as so-called polymer polyols obtained by polymerizing acrylonitrile or styrene or a mixture of both can be used, but polyether polyols are particularly preferably used. They have, for example, a molecular weight of 0 to 90% containing a primary hydroxyl group at the terminal, 3,000 or more 7,
Polyether polyols obtained by adding propylene oxide and ethylene oxide to glycerin are commonly used, and are generally used for the production of general flexible polyurethane foams of 000 or less. Further, when elasticity is particularly required depending on the place of use, the polyol 10
It is preferable to use the above polymer polyol in 5 to 50 parts by weight of 0 parts by weight.

As the polyisocyanate used in the present invention, polyisocyanates generally used in the production of flexible urethane foam can be used. Generally TDI
Is used, but its isomers are 2,4- and 2,6-
Body mixing ratio is 80:20 or 65:35 (weight ratio)
Those having low cost are preferable in terms of practicality. As tolylene diisocyanate, a purified pure product, a crude product or a mixture thereof is used. In addition, especially when flexibility and whiteness of foam are required, this TDI
It is preferably used alone.

A mixture of TDI and another polyisocyanate is also used to enhance the reactivity.
As the other polyisocyanate to be mixed with, for example, pure or crude product of diphenylmethane diisocyanate or a mixture thereof, diphenyl diisocyanate, chlorophenyl-2,4-diisocyanate, P-phenylene diisocyanate, xylylene diisocyanate and polymethylene polyphenylene isocyanate are used. To be The amount of polyisocyanate used relative to the total amount of polyols and other compounds having active hydrogen, that is, the isocyanate index (NCO index) is in the range of 80 to 130, but in the range of 100 to 110 in consideration of the general physical properties of the flexible polyurethane foam produced. Is particularly preferable.

As the catalyst, known ones commonly used in this field can be used. Specific examples thereof include organic metal compound catalysts such as dibutyltin dilaurate, tin octylate and octylzinc, and amine catalysts such as triethylamine, triethylenediamine, N-methylmorpholine and dimethylaminomethylphenol.

In order to adjust the reactivity, it is also possible to use a delayed active catalyst which exerts its catalytic ability after a specific time is reached after mixing the resin solution. These catalysts may be used alone or in combination. The amount of the catalyst used is not particularly limited and can be varied over a wide range, but is preferably 0.1 to 5.0 parts by weight, and particularly preferably 0.5 to 3. parts by weight, based on 100 parts by weight of the polyol usually used in the production of polyurethane foam. 0
Parts by weight are preferred.

As the foaming agent, water or a volatile liquid having a low boiling point, which is a known foaming agent generally used for flexible urethane foam, is used. The volatile liquid having a low boiling point is, for example, trichloromonofluoromethane, dibromodifluoromethane, dichlorodifluoromethane, dichlorotetrafluoromethane, monochlorodifluoromethane, trifluoroethyl bromide, dichloromethane, etc., and these blowing agents are used alone or in a mixture. Can be used.

As the foam stabilizer for making the cells in the foam uniform, there are known silicone foam stabilizers used for foaming polyurethane foam, such as polydialkylsiloxane or polysiloxane-polyalkylene oxide. It is selected from block copolymers, but there is no limitation on the type and the amount thereof as long as the object of the present invention is not impaired. However, especially when focusing on the uniformity of bubbles,
It is preferable to use a single or combined silicone foam stabilizer mainly composed of a polysiloxane-polyalkylene oxide block copolymer. The amount used is 0.5 to 5.0 parts by weight, especially 0.1% by weight based on 100 parts by weight of the polyol.
5 to 2.0 parts by weight is preferable.

Further, pigments known as other additives,
Dyes, flame retardants, antistatic agents, organic / inorganic fillers and the like which are usually compounded at the time of foaming of urethane foam can be used if necessary.

The amount of sericin mixed in the raw material composition is 0.01 to 50 with respect to 100 parts by weight of the polyol.
Parts by weight, preferably 0.1 to 10 parts by weight.
If the amount of sericin added is too small, the effect of the addition of sericin cannot be sufficiently obtained, and if the amount is too large, mechanical properties such as strength of the polyurethane foam deteriorate.

Sericin is dispersed and molded integrally inside the cell membrane and skeleton of polyurethane foam, and the sericin fine spherical particles exposed on the surface of the molding surface directly absorb water and swell, and the absorbed water is molded. It has the function of sequentially feeding into the inner part of the molded product via the sericin particles scattered inside. In addition, since these particles contain a predetermined amount of water and are in a swollen state, the inherent charge of polyurethane foam is prevented, and unpleasant static electricity discharge does not occur.

Example 1 Exenol 828 (polyetherpolyol having a molecular weight of 5000 by adding propylene oxide and ethylene oxide to glycerin, OH value 34.1, manufactured by Asahi Glass Co., Ltd.) 80 parts, Exenol 940 (polyol) Polymer polyol obtained by polymerizing acrylonitrile and styrene at a ratio of 1: 1, OH value 26.4, manufactured by Asahi Glass Co., Ltd., 20 parts, TDI-80 (2,4-body / 2,6-body = 80 / 20 products, NCO% = 48.2%, Sumitomo Bayer Urethane Co., Ltd.) 35.8 parts, SF-2962 (silicone foam stabilizer, Toray Dow Corning Silicone Co., Ltd.) 1 part, water 3 parts, triethanolamine Part 2, Kaurizer No. 1 (tetramethylhexamethylenediamine, manufactured by Kao Corporation) 0.8 part, Niax A-1 (mixed catalyst, manufactured by Union Carbide Co., Ltd.) 0.1 part in a composition consisting of sericin (average particle size 10 μm) 5 The parts were mixed and a polyurethane foam was produced by a conventional method. (Evaluation method) The hygroscopicity of polyurethane was evaluated by the following method. 1) Measure the polyurethane foam at 20 ℃ 65% R
The weight is measured after maintaining in an atmosphere of H or at 40 ° C. and 90% RH for 2 hours. (Measurement value A) 2) The polyurethane foam whose weight after moisture absorption was confirmed in 1) was treated at 105 ° C. for 2 hours and dried completely, and then the weight was measured. (Measured value B) 3) The moisture absorption rate (%) is calculated from the following formula. Moisture absorption rate (%) = (measured value A−measured value B) / measured value B * 100

Example 2 Exenol 3031K (polyether polyol having a molecular weight of 3000 by adding propylene oxide to glycerin, OH value 54.9, manufactured by Asahi Glass Co., Ltd.) 100 parts, TDI-80 (2,4- Body / 2,6-body = 80/20, NCO% = 48.2%, Sumitomo Bayer Urethane Co., Ltd.) 52.1 parts, SH-190 (silicone foam stabilizer, Toray Dow Corning Silicone Co., Ltd.) 1.5 parts, water 4 parts, Dabco-33LV (33% DPG solution of triethylenediamine, AirP product & Chemical Co., Ltd.) 0.3 part, Stanoct T-90 (tin octylate, Kotomi Pharmaceutical Co., Ltd.) 0.3 5 parts of sericin (average particle size 10 μm) is mixed with a composition of 1 part to prepare polyurethane foam by a conventional method. It was.

Comparative Example 1 A polyurethane foam was produced in the same manner as in Example 1 except that sericin was not used.

Comparative Example 2 A polyurethane foam was produced in the same formulation as in Example 2 except that sericin was not used.

The above results are shown in Table 1.

[0029]

[Table 1]

In the polyurethane foams of Examples 1 and 2, it was confirmed by observation with an optical microscope that sericin was dispersed in the cell membrane and the skeleton.

From the above, it is understood that according to the present invention, a polyurethane foam having a hygroscopicity 2 to 5 times higher than that in the case where sericin is not used can be easily obtained.

[0032]

According to the present invention, a polyurethane foam having high hygroscopicity can be easily obtained.

Sericin, which is a by-product that has been conventionally discarded in the silk scouring process, has not been practically worthless, and has a large load on equipment and operating costs in wastewater treatment. As a result of being collected and effectively used, the secondary effect that the value is increased and the above-mentioned load can be greatly reduced can be obtained.

Continuation of the front page (56) References JP-A-6-80741 (JP, A) Kunio Nakamura, Yuko Nishimura, Tatsuko ko Hatakeyama and Hyoethep hinta terpure pineapplea terpure pineapplea terpene a por terpía tinge a por terpía te porpo in Polymer Physics in Japan, Japan, December 7, 1994, Vol. 37, pp. 733-734 Kunio Nakamura, Yuko Nishimura, Tatsuko Hatakeyama, Hyoe Hatakeyama, Thermal and Mechanical Properties of Biodegradable Polyurethanes with Sericin in the Molecular Chain, Journal of the Japan Textile Society, Japan, March 1995, Vol. 51, No. 3, pp. 111-117 (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 18/00-18/87 C08L 74/04-75/16 C08L 89/00 JISST file (JOIS)

Claims (2)

(57) [Claims] 1. A spherical powder of sericin having an average particle size of 20 μm or less in a foam film and skeleton of polyurethane foam.
Polyurethane foam dispersed . 2. When a polyurethane foam is produced by reacting a composition containing a polyol, a polyisocyanate, a catalyst and a blowing agent, 0.01 to 50 parts by weight of 100 parts by weight of the polyol has an average particle size of 20 μm or less.
The method for producing a polyurethane foam according to claim 1 , wherein the reaction is carried out in the presence of spherical powder of lysine .