JPH0342353B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a cushion body mainly made of synthetic resin. Urethane foam formed by foaming is often used as cushion bodies for vehicle seats such as automobiles, furniture chairs, bedding, and the like. However, for bedding and the like, synthetic fiber cushions are being replaced because they have a texture that cannot be obtained with urethane foam. Synthetic fiber cushions developed for such uses have weak tissues, so they cannot be used as vehicle seat cushions because they do not have the necessary hardness and may feel bottomed out, or may not recover properly. The fact is that they have poor sexuality, and even worse, they are suffering greatly. Furthermore, attempts have been made to subject such synthetic fiber cushions to crimping, resin treatment, addition of low melting point binders, etc., but none of these treatments have been able to solve the above-mentioned problems. I wasn't there. In manufacturing a cushion body using synthetic fibers, the present invention uses a urethane prepolymer and reacts it to obtain a cushion body that has good breathability, sufficient cushioning properties, and less sag. This solves the above-mentioned problems. That is, the present invention comprises a step of opening synthetic fibers to form a fiber sheet in which the fibers are three-dimensionally entangled, a step of coating the fiber sheet with a urethane prepolymer containing active terminal isocyanate groups, and a step of coating the fiber sheet with a urethane prepolymer containing active terminal isocyanate groups. The method is characterized by comprising a step of laminating the laminated fiber sheets in a mold, and a step of pressing the laminated fiber sheets into a predetermined shape and then reacting the isocyanate groups with an active compound. The present invention will be explained in more detail below. As the synthetic fiber in the present invention, polyester fibers such as polyethylene terephthalate, polyhexamethylene terephthalate, and polytetramethylene terephthalate are used. This synthetic fiber is opened and the individual fibers are intertwined three-dimensionally to form a predetermined sheet shape. For this reason, synthetic fibers need to have appropriate fineness and fiber length.
The fineness is selected within the range of 2 to 10 deniers, and the fiber length is selected within the range of 30 to 70 mm. Such a synthetic fiber sheet is coated with a urethane prepolymer, and this coating treatment can be easily performed by dipping or spraying. Through this coating, the urethane prepolymer adheres to the fiber surface of the synthetic fiber sheet and to the bonding points between the fibers, and the fiber structure is strengthened by the reaction described below, thereby imparting appropriate hardness and cushioning properties. The urethane prepolymer is produced by synthesizing polyether polyol and isocyanate, and has two active terminal isocyanate groups.
Since it contains ~7%, it is highly reactive. The synthetic fiber sheet coated with this urethane prepolymer is then set in a predetermined mold and reacted with the isocyanate group-active compound. This reaction is a so-called polymerization reaction in which isocyanate groups are bonded together with an active compound, and the sheet is appropriately cured by this reaction to obtain the desired cushion body. The active compounds used are alcohols, polyols, amines, ammonia or water. FIG. 1 shows a flowchart of the present invention, in which the urethane prepolymer is coated and the synthetic fiber sheets are set in a layered manner in a mold, and then pressed to react the isocyanate groups. Hereinafter, specific examples will be explained using examples and comparative examples. Example 1 A conjugate type polyester fiber having a fineness of 6 denier and a fiber length of 51 mm was opened to form a sheet with a thickness of 20 mm, and a urethane polymer was sprayed onto this sheet using a spray device. In this case, the urethane prepolymer was synthesized in advance as follows. A polyether polyol with a terminal ethylene oxide addition rate of 15%, an average molecular weight of 1,500, an average number of functional groups of 3, and a hydroxyl value of 112 was used. After dehydrating this polyether polyol, 1,000 g was placed in a three-necked flask, and an isocyanate (T- 80) 309g
was added and stirred at 80°C for 1 hour to complete the synthesis. The obtained urethane prepolymer contained 5% of isocyanate groups (-NCO). When spraying this urethane prepolymer, Freon 11 was added to dilute it to 5% by weight to lower the viscosity. Next, seven synthetic fiber sheets coated with urethane prepolymer were stacked in a 300 x 300 x 50 mm mold, and after being pressed with an upper mold, pressurized steam was introduced into the mold to react with the isocyanate groups. After it was cured, it was taken out from the mold to obtain a cushion body. Example 2 The urethane prepolymer of Example 1 diluted to 5% by weight with Freon 11 was sprayed onto a polyester fiber sheet that had been opened in the same manner as in Example 1, and this sheet was placed in a mold of 300 x 300 x 50 mm. After laminating the sheets and pressing them with an upper mold, pressurized ammonia vapor was introduced into the mold to harden them to obtain a cushion body. Comparative Example 1 Seven polyester fiber sheets with a thickness of 20 mm created by spinning in the same manner as in Example 1 were stacked in a mold of 300 x 300 x 50 mm, and after pressing with an upper mold, the sheets were heated at 130 to 150 °C in the mold. After cooling, the mold was taken out from the mold. Comparative Example 2 A low-melting polyester fiber having a fineness of 4 denier and a fiber length of 51 mm was mixed with the same polyester fiber as in Example 1 at a ratio of 7:3, and the mixture was opened to produce a synthetic fiber sheet with a thickness of 20 mm. This sheet is 300×300×
Seven sheets were stacked in a 50 mm mold, pressed with an upper mold, and then pressurized steam was introduced into the mold to melt the low melting point polyester fibers and thermally fuse the polyester fibers together, and then removed from the mold. Table 1 compares the physical properties obtained in the above Examples and Comparative Examples with those of cushion bodies made of urethane foam.

[Table] The cushion body obtained by the present invention described above has good breathability because it is made of synthetic fiber as a base material, has the necessary hardness for a cushion body, has little set-up, and is lightweight. It has the feature that

[Brief explanation of drawings]

FIG. 1 is a manufacturing process diagram of the present invention.

Claims (1)

[Claims] 1. A step of spinning synthetic fibers into a fiber sheet in which the fibers are three-dimensionally intertwined, and a step of coating the fiber sheet with a urethane prepolymer containing active terminal isocyanate groups. A method for manufacturing a cushion body, comprising the steps of: laminating coated fiber sheets in a mold; and pressing the laminated fiber sheets into a predetermined shape, and then reacting an active compound with an isocyanate group.