JP2883764B2 - Cutting method of polyurethane sheet laminate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a cutting or punching process for producing a secondary product using a polyurethane sheet.

[0002]

2. Description of the Related Art A sheet material such as a polyurethane nonwoven fabric or a polyurethane film is used as a raw material, and a plurality of such materials are stacked and cut into a predetermined shape by a press-cutting cutter, commonly known as a guillotine cutter, or specified using a mold. Punching and drilling the shape (for convenience,
The word "cutting".) For example, ear cutting for removing non-uniform parts at both ends in the sheet width direction, cutting into a predetermined shape, collection of punched products of a specific shape,
Perforations for obtaining ventilation holes correspond to this. that time,
There is an inconvenience that the upper and lower layers are adhered and integrated on the cut surface and are not separated one by one (hereinafter, referred to as union).

[0003] A technique for blending a lubricant to prevent blocking of a polyurethane product (Japanese Patent Application Laid-Open No. 1-298259) has been proposed, but a technique for preventing coalescence at the time of cutting has not yet been proposed.

[0004]

It is supposed that the coalescing phenomenon occurs because the fibers of the upper and lower layers are united by the compressive shearing action at the time of cutting by cutting. This phenomenon occurs for a long time after winding, and even after the apparent surface tackiness has disappeared, if a plurality of sheets are laminated and cut, the above-mentioned inconvenient union occurs on the cut surface. In particular, a product having a lower urethane hardness has a stronger tendency to unite.

[0005] This phenomenon also occurs when a plurality of sheet products obtained by laminating a urethane nonwoven fabric and a urethane film are laminated and cut, or when both are alternately overlapped and cut. In this case, it is necessary to carefully separate the united portions by hand so as not to be broken one by one, which results in waste of time and a reduction in efficiency. An effective method for preventing this coalescence phenomenon has not been found so far, and a countermeasure has been desired.

[0006]

As a result of various studies, the present inventors have found that only a specific organic higher-chain carboxylic acid amide compound has this effect, and have completed the present invention. That is, according to the present invention, when a plurality of polyurethane sheets are laminated and cut, (CH ₂ )
an organic higher-chain carboxylic acid amide compound represented by n (NHCOR) ₂ and / or RCONH ₂ (where n is 1 or 2, and R represents a saturated or unsaturated hydrocarbon group having 13 to 25 carbon atoms) 0.05 to 1.5% by weight
This is a method for cutting a polyurethane sheet laminate characterized by blending.

The polyurethane nonwoven fabric applicable to the present invention is a nonwoven fabric having a structure in which polyurethane elastic fibers are randomly entangled by its own adhesiveness. It is obtained by spunbonding by melt spinning or dry spinning or melt blowing.
177 and Japanese Patent Publication No. 1-30945. Examples of the polyurethane film applicable to the present invention include known films manufactured by a T-die method, a dry method, and a wet method.

[0008] Examples of the organic higher chain carboxylic amide compound to be incorporated into the polyurethane sheet in the present invention include stearamide, palmitic amide, oleic amide, methylenebis-stearamide, ethylenebis-stearamide, ethylenebis-oleylamide and the like. There is. Particularly, ethylene bis-stearamide and ethylene bis-oleyl amide are preferable.

The amount of the organic higher chain carboxylic acid amide compound added to the polyurethane sheet is preferably 0.15 to 1.5% by weight, and when the added amount is less than 0.05% by weight, the effect of preventing coalescence is reduced. When it is not obtained, and when the content exceeds 1.5% by weight, the effect of preventing coalescence is improved, but the compatibility with addition to polyurethane becomes poor. When the sheet is a nonwoven fabric, this causes thread breakage during spinning or lowers the adhesiveness of the fibers constituting the nonwoven fabric, resulting in inconvenience such as impairing mechanical properties such as tensile strength of the nonwoven fabric. In the case of a film, the transparency of the product is adversely affected.

As a method for adding the organic higher chain carboxylic acid amide compound to a polyurethane nonwoven fabric and a film, a known method can be adopted, and may be added at the time of polymerization of the polyurethane, or added to the polyurethane at the time of processing into a nonwoven fabric or a film. You may mix.

[0011]

[Function] The coalescing phenomenon of the fiber or film in the cut surface can be understood by observing the cut surface with an enlarged photograph such as an SEM. "Integration" occurs to such an extent that it is impossible to determine whether or not the objects are separated, which indicates that they cannot be separated from each other.

Although it was expected that the addition of known lubricants and release agents to plastic products would be effective in preventing the coalescence of the polyurethane sheet as described above, various inorganic compounds, organic higher esters and higher carboxylic acid metals were expected. Salt compounds,
It cannot be achieved by other waxes, and only the specific higher organic carboxylic acid amide compound of the present invention has this action. Although the detailed reason for this is not clear, it is presumed that the compound improves the urethane cleavability and can significantly prevent the coalescence phenomenon at the time of cutting.

It is a common practice to mix various lubricants and release agents into plastic products, for example, to improve the fluidity of resin during extrusion or injection molding,
It is used for the purpose of improving the releasability from a mold or the like in the melt processing step, or used for the purpose of preventing sticking due to adhesion between products.

A technique for blending a lubricant to prevent blocking of a polyurethane product is certainly a known technique. For example, a high-carboxylate compound, an amide compound, and a calcium compound may be added to a melt-blown spun yarn of urethane. A proposal for compounding a salt compound is disclosed in Japanese Patent Application Laid-Open No. 1-298259.
No., published in Japanese Patent Application Publication No. The purpose is to melt the polyurethane after melt-blowing and still take up while the polymer is incompletely cooled and the tackiness remains. In order to solve the problem, the above compound is blended. Therefore, the object is to be implemented in anticipation of the anti-sticking action based on the residual tackiness of the upper and lower two layers in a planar contact state.

On the other hand, in the present invention, when a plurality of polyurethane sheet-like products are laminated and then cut in a compressed state, the shearing and unifying of the fiber and the film is suppressed, and the plurality of polyurethane sheet-like products are easily separated from each other without being united. Therefore, the action is not the same (easiness of cutting, improvement of cutting property). Therefore, the novelty of the present invention exists there.

[0016]

【Example】

Example 1 Diphenylmethane diisocyanate (MDI), polybutylene adipate having a molecular weight of 2000 (PBA200)
0) A thermoplastic polyurethane composed of 1,4-butanediol (BD) and having a hardness of 90 (JIS 7311 A method) was melted at a temperature of 228 ° C. by an extruder, while being provided in an intermediate zone of the extruder. Ethylene bis-stearic acid amide was added and kneaded at a controlled rate of 0.75% by weight from the vent hole, and was spun into a filament form from a number of linear nozzles set at a temperature of 230 ° C. The filaments were immediately drawn and entangled with heated air at a temperature of 233 ° C. at an outlet pressure of 1.8 kg / cm ² , which was ejected from slits on both sides of the nozzle row, and were collected on a conveyor net placed 30 cm below the nozzle. The basis weight of the nonwoven fabric obtained by controlling the spinning amount and the conveyor speed was 50 g / m ² .

Next, 20 nonwoven fabrics were laminated, and compression punching was performed from above using a punching machine for making dumbbell pieces. The 20 pieces that were punched out were cut off one by one without any coalescence.

Example 2 The nonwoven fabric obtained in Example 1 and a hardness of 85 (JIS 73)
11A method), a laminate of 10 sheets of a thermoplastic polyurethane film “Milactran E585P” (manufactured by Nippon Milactran Co., Ltd.) having a thickness of 70 μm, which is a total of 10 sheets, is B5 size with a handle lever type document cutting machine. Cut into pieces. It was possible to separate each of the films and the non-woven fabric one by one simply by lightly cutting the cut surface.

[0019]

According to the present invention, it is possible to easily prevent the coalescence of cut surfaces generated when cutting a laminate or laminate made of a urethane nonwoven fabric or urethane film by adding a specific compound to the urethane nonwoven fabric. It is possible to contribute to the improvement of the efficiency of the cutting process. It is also possible to avoid breakage that often occurs due to forcible separation of the joining points. Further, since the required addition amount of the compound is small, it does not adversely affect the physical properties of the nonwoven fabric and the production process.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B26D 1/08 B26D 3/16 B26D 3/00 601

Claims (3)

(57) [Claims] When a plurality of polyurethane sheets are laminated and subjected to press-cutting, punching or punching, the sheets are preliminarily (CH ₂ ) n (NHCOR)
₂ and / or RCONH ₂ (where n represents 1 or 2 and R represents a saturated or unsaturated hydrocarbon group having 13 to 25 carbon atoms). A method for cutting a polyurethane sheet laminate, wherein the polyurethane sheet is blended in an amount of from 1.5 to 1.5 wt%. 2. The method according to claim 1, wherein the polyurethane sheet is a polyurethane nonwoven fabric. 3. The method according to claim 1, wherein the polyurethane sheet is a laminate of a polyurethane nonwoven fabric and a polyurethane film.