JPH0541748B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a transfer sheet for producing synthetic leather, which is used to obtain synthetic leather having a surface with a fine embossed pattern.

[Conventional technology]

Synthetic leathers with various types of synthetic resin layers such as polyvinyl chloride, polyamide, polyurethane, and polyamino acid are manufactured on the surface, but these synthetic leathers especially have embossed patterns and embossed patterns similar to natural leather. There is a demand for something with luster. For this purpose, the surface of the obtained synthetic leather is usually pressed with a molding roll, or various synthetic resins are applied to the surface pressed by the molding roll of a transfer sheet made of a release shot whose surface is pressed with a molding roll. A method of obtaining synthetic leather with an embossed pattern on the surface by applying the coating, then adhering a base fabric for synthetic leather to the coated surface, and then peeling off and removing the transfer sheet from the obtained laminated sheet. is being used.

[Problem that the invention seeks to solve]

By the way, in all of the methods described in the "Prior Art" section, the shape of the convex part which is the molding part of the molding roll used is an upper hemisphere, a rectangular parallelepiped,
Since the synthetic leather has a cubic shape, etc., if you want to introduce a large number of microscopic depressions on the surface of the synthetic leather and make the effect obtained by the microscopic depressions about the same as a matte effect,
The attenuation rate of the incident light rays is large at the location where the micro-concavity group is formed, and it is difficult to obtain an extremely matte effect. Especially in the case of a partially matte part, there is a difference between the matte part and the non-matte part. Since the difference in appearance between the matte portion and the matte portion is too large, it has the disadvantage that a gentle matte effect cannot be obtained.

[Means for solving problems]

The present invention relates to a method for producing a transfer sheet, which is used when introducing a fine uneven pattern formed on the releasable surface of the transfer sheet onto the surface of synthetic leather. The present invention provides a method for manufacturing a transfer sheet for manufacturing synthetic leather having a novel structure having a group of minute protrusions formed of a collection of minute protrusions in the shape of a pyramid that converges in one direction.

The method for manufacturing a transfer sheet for manufacturing synthetic leather of the present invention involves applying electronic engraving to a copper cylinder or copper plate using the heliochrysiograph method using a color-separated black-and-white continuous-tone reflective original or black-and-white transparent original as a base paper, Obtaining an engraved cylinder or an engraved plate with an engraved pattern consisting of a group of minute recesses having a density and depth depending on the light transmittance of the base paper, the engraved pattern on the engraved cylinder or the engraved plate. is transferred onto the releasable surface of a release sheet substrate, at least one surface of which is a releasable surface, by heating and pressurizing, thereby forming a group of minute recesses of the engraved pattern on the engraving cylinder or engraving plate and their irregularities. This method consists of obtaining a transfer sheet having a group of minute protrusions in which the relationship is reversed.

In the first step of the method for producing a transfer sheet for producing synthetic leather according to the present invention, an engraved cylinder or plate is obtained by the heliochrysiograph method, which is a type of electronic engraving plate making. Electronic engraving plate making using the heliochrysiograph method uses a diamond needle with a pyramidal tip as an engraving head needle, which increases the light transmittance of the base paper.
This is an engraving method with a mechanism in which the depth of cut by the needle of the engraving head is controlled by the strength or weakness of the photocurrent depending on the size of the cut. It is formed in the shape of a pyramid that converges toward the inside. Therefore, in the first step, the black-and-white continuous-tone reflection or black-and-white transmission that the base paper has reflects the depth of the recesses constituting the micro-recess group and the opening area of the pyramid-shaped recesses that converge toward the inside. It has the characteristic of being extremely faithfully converted to size and embodied on a carved cylinder or carved plate.
The copper cylinder or copper plate used as the electronic engraving plate obtained by the above method is used for the purpose of reinforcing the engraved surface before being used in the second step of the method for producing a transfer sheet for producing synthetic leather of the present invention. It is common that chrome plating is applied to the surface.

In the second step of the method of the present invention, the engraved pattern on the engraved cylinder or plate obtained in the first step is applied to the releasable surface of the release sheet base, at least one surface of which is a releasable surface. An embossed pattern in which the uneven pattern is reversed to the engraving pattern, which is transferred by heating and pressure, that is, a group of minute protrusions consisting of a collection of minute convexities in the shape of pyramids that converge toward the outside. To obtain a transfer sheet for synthetic leather production, which has a releasable surface. Book 2
The release sheet substrate used in the process may be a sheet-like material with at least one surface having a release property, and may be a single sheet made of a film-formable synthetic resin that has release properties. , or a base sheet composed of a base sheet and a releasable resin layer formed on the base sheet, or even a base sheet whose surface is treated with a metal salt of a higher fatty acid. Although it is possible to use a release sheet as a base, it is most common to use one composed of a base sheet and a release resin layer as the release sheet base. Examples of the base sheet in the release sheet base having the above structure include single-glazed bleached kraft paper, kraft paper, roll paper,
In addition to high-quality paper and nonwoven fabric, various synthetic resin films and sheets, metal foils such as aluminum, laminated paper of paper and resin film or metal foil, etc. are used. In addition, the surface of the releasable resin layer on the base material sheet has releasability, but it is also possible to use the releasable resin layer on the surface of the releasable resin layer to form an electronically engraved engraving cylinder or engraving plate. It is necessary that the engraved pattern can be easily transferred and that the transferred uneven pattern shape can be maintained on the surface of the mold release resin layer. For example, modified silicone resin modified with silicone resin, amino alkyd resin, epoxy resin, etc. , thermosetting resin, polyolefin resin, etc.

〔Example〕

Examples of the method for producing a transfer sheet for producing synthetic leather according to the present invention will be described below with reference to the drawings.

The base paper consists of patterned paper with a black and white dot lattice pattern on which the plain area appears in a lattice pattern.
Using an engraving head consisting of a pyramidal diamond needle, the surface of the copper cylinder was electronically engraved by the heliochrysiograph method, and then the engraved surface of the obtained copper cylinder was chromed. , an engraved cylinder with improved surface hardness was obtained.

Next, a release sheet substrate indicated by reference numeral 1 in FIG. 3, that is, a base sheet 2 made of single-gloss bleached kraft paper with a basis weight of 143.5 g/m ² and a sheet with a melting point of 162° C. The release resin layer 3 of the release sheet base 1 is composed of the release resin layer 3 having a thickness of about 30 μm and formed by extrusion coating polypropylene for extrusion. The engraved pattern from the previous engraved cylinder was transferred onto the surface by a heating and pressing method to obtain a transfer sheet for producing synthetic leather indicated by reference numeral 4 in FIGS. 1 and 2. The transfer of the above-mentioned release sheet substrate 1 to the release resin layer 3 was carried out at 115°C and at 70kg/
The experiment was carried out under heating and pressure conditions of cm ² .

Thus, by the above process, the parts 6, 6, ... whose surfaces exhibit a mirror surface, and the parts whose outline shape is an aggregate shape of minute pyramids 7, 7, ... whose outer shape converges toward the outside. A transfer sheet 4 for manufacturing synthetic leather was obtained in which a releasable resin layer 5 composed of 8, 8, . . . was formed on one side of the base sheet 2.

Experiment A urethane resin was applied almost uniformly to the surface of the release resin layer 5 of the transfer sheet 4 for synthetic leather production obtained in the above example at a solid content of about 30 g/m ² , and after drying. Liquid urethane resin adhesive in solid content
When the above-mentioned transfer sheet 4 was peeled off and removed from the laminated sheet obtained by overcoating at a rate of 50 g/m ² and further adhering a cotton knitted cloth and drying, the micro pyramids 7 in the transfer sheet 4 were removed. , 7, ... The surface corresponding to the part 8, 8, ... forming the aggregate shape is
A synthetic material with a mild matte surface that exhibits a mild matte effect with weak light reflection, and does not cause discomfort due to the light reflection of mirror surfaces that do not have a matte effect. Leather was obtained.

[Action and effect]

The method for manufacturing a transfer sheet for manufacturing synthetic leather of the present invention has the above-mentioned configuration, and includes an engraved pattern on an engraved cylinder or an engraved plate that is electronically engraved using the heliochrysiograph method, so that at least one surface of the engraved pattern is separated. It is transferred onto the mold release surface of the mold release sheet substrate by heating and pressurizing.

That is, the engraving pattern on the engraving cylinder or engraving plate used in the method of the present invention is composed of a group of incisions made by a diamond needle whose tip is a pyramid, that is, it is composed of minute pyramids that converge toward the inside. The depth of the cut made by the diamond needle is controlled by the strength or weakness of the photocurrent depending on the light transmittance of the cardboard. The convergent pyramid shape is formed as a group of minute pyramids in which the depth of the concave portion and the area of the opening serving as the concave portion are correlated.

Therefore, the transfer sheet for synthetic leather production according to the method of the present invention, in which the engraved pattern on the engraved cylinder or the engraved plate having the above structure and the uneven pattern in which the uneven relationship is reversed, is transferred to the release surface. On the surface of the synthetic leather produced, a large number of concave portions in the shape of minute pyramids that converge toward the inside are formed, so that a gentle matte effect with weak light reflecting power is obtained in these portions. , the ability to obtain synthetic leather with a high design quality and a high quality feel;
It is effective.

In addition, in the method of the present invention, the engraved pattern on the engraved cylinder or engraved plate when obtaining the transfer sheet for synthetic leather production is formed by electronic engraving plate making using the heliochrysiograph method, so the pattern on the base paper is faithful. Since it is formed in the form of a carved pattern, it is possible to obtain a synthetic leather having a matte effect with a variety of gradations and textures.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional end view schematically showing an example of a transfer sheet obtained by the method of manufacturing a transfer sheet for producing synthetic leather of the present invention, FIG. 2 is a front view thereof, and FIG.
The figure is an enlarged sectional view schematically showing the release sheet substrate used to obtain the transfer sheet shown in FIG. 1. 1: Release sheet base, 3: Release resin layer in release sheet base 1, 4: Transfer sheet for synthetic leather production, 5: Release resin layer in transfer sheet 4 for synthetic leather production.

Claims (1)

[Claims] 1. An engraved pattern on an engraved cylinder or engraved plate electronically engraved by the heliochrysiograph method using a color-separated black-and-white continuous-tone reflective original or black-and-white transparent original as a base paper, with at least one surface having a releasable surface. A method for producing a transfer sheet for producing synthetic leather, characterized in that the transfer sheet is transferred onto the releasable surface of a release sheet substrate using a heating and pressurizing method.