JPH0939092A - Manufacture of embossed sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously manufacture an embossed sheet while uniformizing the thickness of the embossed sheet after emboss processing and holding processed embossed shapes without requiring many cooling rolls in the cooling of the embossed sheet after emboss processing. SOLUTION: In a method supplying a thermoplastic resin sheet to an embossing roll to produce an embossed sheet, the thermoplastic resin sheet heated to temp. higher than Clash-Berg flexible temp. by 50-150 deg.C is pressed and cooled between the embossing roll and the backup roll held to the Clash- Berg flexible temp. of a thermoplastic resin or less to cool the temp. of the embossed sheet peeled from the embossing roll to the Clash-Berg flexible temp. +15 deg.C or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an embossed sheet in which the surface of a thermoplastic resin sheet is embossed. The embossed sheet is particularly used for a floppy disk jacket, a remote control face sheet,
It is also used for various packaging materials and building surface materials that require fingerprint resistance and low gloss.

[0002]

2. Description of the Related Art Conventionally, a method for producing an embossed sheet made of a thermoplastic resin is disclosed in Japanese Examined Patent Publication No. 4317/1992. Keep the temperature 20 to 120 ° C higher than the temperature, supply the thermoplastic resin sheet with the backup roll (silicone rubber roll) and press it, then peel the thermoplastic resin sheet from the embossing roll and set a large number of cooling rolls. A method of obtaining an embossed sheet by gradually cooling it using a glass transition temperature. As disclosed in JP-A-5-16229, as a method for producing a double-sided embossed sheet, a vinyl chloride resin sheet is preheated to a surface temperature of 180 to 200 ° C, and then an embossing roll of 60 ° C and an inorganic filler of 60 ° C are used. There is a method such as pressure bonding with a textured backup roll.

In these conventional techniques, a thermoplastic resin sheet having a uniform thickness, which is a base material of an embossed sheet obtained by calendering, extrusion molding or the like, has an embossing roll at a high temperature and has an uneven pattern formed on the surface. As a result, the peelability of the embossed sheet from the embossing roll tends to decrease, and the unstable peeled embossed sheet is drawn with a constant force and stretches in the peeling direction, thereby making the thickness of the embossed sheet uneven. Was becoming.
Further, when the embossed sheet is stretched, the unevenness on the surface of the embossed sheet formed by the embossing roll also extends, resulting in a disadvantage that the unevenness becomes shallower than that at the time of molding. Further, when the embossed sheet peeled from the embossing roll is rapidly cooled on the cooling roll, the embossed sheet partially causes uneven cooling, and wrinkles and deformation are likely to occur in the part, and therefore, usually many It was necessary to cool gradually using a chill roll. Furthermore, in the conventional technology, the conditions for setting the temperature of the embossing roll and the backup roll have not been sufficiently studied, and since the temperature is simply 60 ° C., the relationship with the production speed is not sufficiently understood, so the actual Since the manufacturing process did not sufficiently cope with the change in the production speed, defects such as unevenness of the sheet surface and an embossed sheet with unstable gloss occurred. For example, when manufactured by the conventional technology, the temperature of the backup roll is 70 to 70 due to the heat from the heated thermoplastic resin sheet (120 to 200 ° C) that is received when the emboss roll and the backup roll are pressed.
It will be 150 ℃. This temperature is greatly affected by changes in the production speed, and when the production speed increases, heat is accumulated and the backup roll temperature rises even higher.
When the temperature is 80 ° C. and the backup roll temperature is 80 ° C., the releasability of the embossed sheet from the backup roll is reduced, and thus the adhesion to the embossed roll is poor, resulting in an uneven embossed sheet having a low level of unevenness. Further, the above example is a manufacturing method limited to a special processing method called double-sided embossing.

[0004]

DISCLOSURE OF THE INVENTION The present invention does not require many cooling rolls for cooling the embossed sheet after embossing, and the embossed sheet after embossing has a uniform thickness and retains the processed uneven shape. It is an object to continuously manufacture the embossed sheet and to derive a clear relationship between the temperature of the backup roll and the temperature of the embossed sheet peeled from the embossing roll to enable the stable production of the embossed sheet. .

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted many experiments to solve the above technical problems, and as a result, have found that the crushberg of the thermoplastic resin sheet for processing the backup roll temperature is crushed. The inventors have found that it is sufficient to keep the softening temperature (hereinafter referred to as the softening temperature) or less and to set the temperature of the embossed sheet peeled from the embossing roll to the softening temperature plus 15 ° C. or less, and established the various conditions to complete the present invention. The gist of the method is to supply a preformed thermoplastic resin sheet to an embossing roll to produce an embossed sheet.
The temperature of the embossed sheet that is peeled from the embossing roll by pressing and cooling the thermoplastic resin sheet heated to a high temperature with the embossing roll and the backup roll kept below the Crushberg flexibility temperature of the thermoplastic resin sheet. The method for producing an embossed sheet is characterized in that the Crushberg is cooled to a soft temperature plus 15 ° C or less.

Hereinafter, the present invention will be described in detail. As the thermoplastic resin used in the present invention, a vinyl chloride resin,
Low-pressure polyethylene, high-pressure polyethylene, polyester,
Polystyrene, polypropylene, polyvinylidene chloride,
Polymethylpentene, polyvinyl alcohol, methacrylic resin, fluororesin, polycarbonate, polybutene-
1, thermoplastic polymers such as polyamide, ethylene-vinyl acetate copolymer, butadiene resin, acryl-styrene resin, acrylonitrile-butadiene-styrene resin, etc., blends, copolymers, etc., but especially vinyl chloride Resins are preferred. The vinyl chloride resin includes, in addition to vinyl chloride homopolymer, 50% by weight or more of a vinyl chloride monomer and a copolymer with a vinyl monomer copolymerizable therewith. As copolymerizable vinyl-based monomers, olefins such as ethylene and propylene;
Halogenated olefins other than vinyl chloride such as vinylidene chloride and vinyl fluoride; vinyl esters such as vinyl acetate and vinyl laurate; alkyl vinyl ethers such as 2-ethylhexyl vinyl ether and dodecyl vinyl ether; acrylic acid, methyl acrylate, acrylic Acrylic acid or its esters such as ethyl acidate; Methacrylic acid or its esters such as methacrylic acid, methyl methacrylate, 2-ethylhexyl methacrylate; Maleic acid or its esters; Acrylic systems such as maleic anhydride, acrylonitrile, styrene, etc. Derivatives: N-t-butylmaleimide, N-cyclohexylmaleimide, etc.
Substituted maleimides are mentioned, and these are used individually or in combination of 2 or more types. If necessary, the thermoplastic resin further contains stabilizers, fillers, ultraviolet absorbers, colorants, lubricants, plasticizers, antistatic agents, processing aids, antioxidants, flame retardants, and other resin components. Additives such as

The manufacturing method will be described with reference to FIG. 1. A thermoplastic resin sheet (hereinafter referred to as a sheet) 1 which has been formed into a required thickness in advance by a calendar or a T-die extruder, or directly formed from these forming machines. The sheet thus prepared is heated by the preheating roll 3 to a temperature 50 to 150 ° C. higher than the softening temperature of the thermoplastic resin sheet. The sheet temperature mentioned here indicates the surface temperature of the sheet. Moreover, you may heat with the heater 4 as needed. At this time, if the temperature of the heated sheet is less than the soft temperature of the sheet plus 50 ° C, the unevenness of the surface of the obtained sheet becomes insufficient, and the soft temperature of the sheet plus 150
When the temperature exceeds ℃, the melt viscosity of the sheet itself is lowered and it becomes difficult to peel it from the preheating roll 3. The sheet heated by the preheating roll 3 is supplied between the embossing roll 7 and the backup roll 5 whose temperature is adjusted to the soft temperature of the sheet or lower, pressed, cooled, and brought into close contact with the embossing roll 7, and then the embossing roll 7. The embossed sheet peeled off from the sheet is cooled on the embossing roll to the soft temperature of the sheet plus 15 ° C or less. At this time, the temperature of the embossed sheet is measured within 10 cm away from the embossing roll and almost at the center of the embossed sheet. The sheet adhered to the embossing roll 7 is peeled off by the peeling roll 8 and wound as a product (embossing sheet) 10. If necessary, the cutter 9 may be used to obtain a sheet-shaped product (embossed sheet).

Here, the temperature of the sheet cooled by the embossing roll 7 is the soft temperature of the sheet plus 15 ° C.
When it exceeds the above range, the thickness of the embossed sheet peeled from the embossing roll becomes non-uniform, and the uneven shape of the embossing on the surface extends, so that a good embossed sheet cannot be obtained. Therefore, the temperature of the embossing roll is adjusted as necessary in order to keep the temperature of the embossing sheet peeled from the embossing roll to be less than the softening temperature plus 15 ° C. For example, when the production rate is 15 m / min using a vinyl chloride resin sheet, the embossing roll temperature is adjusted to 40 to 60 ° C.

Regarding the temperature setting of the backup roll, when the temperature of the embossing roll is near the soft temperature, the temperature of the backup roll is usually a high temperature (120 to 23) which is received when the embossing roll and the backup roll are pressed.
The heat from the sheet heated to 0 ℃) accumulates and 60 to 150
Rise to ℃. When the temperature of the backup roll rises above the softening temperature, the peelability of the embossed sheet from the backup roll deteriorates, resulting in poor adhesion to that portion. In this poorly adhered portion to the embossing roll, the embossed sheet is insufficiently cooled and the embossed uneven shape is not cooled, so that the embossed sheet is stretched and a desired uneven shape cannot be obtained. Moreover, in order to further cool the backup roll, if necessary, it is preferable that the cooled backup roll surface cooling roll 6 is directly attached to the backup roll. This increases the cooling effect. As a temperature adjusting method for the preheating roll 3, the embossing roll 7, and the backup roll surface cooling roll 6, steam, a heat medium, water for use or chiller water is used as necessary. As a method of adjusting the temperature of the backup roll 5, a method of bringing the above-mentioned backup roll surface cooling rolls 6 into contact with each other, a method of applying a cooling medium such as water or chiller water, and a method of combining these are adopted.

The embossing roll is usually formed by corroding, engraving or blasting the surface of a metal roll to form a concavo-convex shape with a center line average surface roughness of 3 to 10 μm. The backup roll is a metal core bar roll. A silicone rubber layer is adhesively formed on the surface, and the pressing pressure of the sheet by both may be 5 kg / cm or more. It is also possible to manufacture a double-sided embossed sheet using a textured backup roll in which an inorganic filler is mixed in the backup roll.

The Crashberg soft temperature used in the present invention is a thermoplastic resin measured by JIS K6734.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The function of the present invention is to set the temperature of a heated sheet to a temperature which is 50 to 150 ° C. higher than the softening temperature of the sheet, supply it between an embossing roll and a backup roll, and press and cool it. By doing so, sufficient adhesion can be achieved to the embossed roll uneven portion. Also, the temperature of the embossed sheet peeled from the embossing roll is set to a soft temperature of the sheet plus 15 ° C or less, so that the embossing roll is uniformly peeled off and taken off with a constant force, so the transferred uneven shape is maintained and the sheet thickness That is, a uniform embossed sheet can be obtained. Furthermore, it is because the cooling roll for cooling the embossed sheet peeled from the embossing roll, which is usually required, is no longer required.

[0013]

EXAMPLES The embodiments of the present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. (Example 1) Composition of a sheet Weight part Vinyl chloride resin (manufactured by Shin-Etsu Chemical Co., Ltd., degree of polymerization 700) 100 MBS resin (methylmethacrylate / butadiene / styrene copolymer resin, B-56 manufactured by Kaneka Corporation) 10 Stabilizer (calcium type) 3 Plasticizer (epoxy type) 1 Filler (talc) 5 Lubricant (amide type) 1 Face agent (carbon black) 2 After mixing the above composition with a Henschel mixer, thickness using a calendar After forming a 0.2 mm sheet, embossing was performed. The soft temperature of this sheet is 70 ° C. First, mold the molded thermoplastic resin sheet at 160 ° C (soft temperature +
After adjusting the temperature to 90 ° C), the temperature of the roll is adjusted to 50 ° C, the embossing roll having a center line average roughness of 5 to 6 μm on the surface of the roll, the backup roll having the silicone rubber on the surface and the temperature of 70 ° C, and the backup roll. Was carried out at a line production speed of 30 m / min using an embossing device equipped with a cooling roll for cooling. At that time, the temperature of the embossed sheet peeled from the embossing roll was about 70 to 80 ° C. The embossed sheet obtained under the above manufacturing conditions has a sheet thickness of 0.2 mm and a center line surface roughness of the sheet surface of 4 mm.
The embossed sheet had a uniform thickness of μm. The fingerprint resistance was good and the surface glossiness was 3 to 4%.

(Comparative Example 1) Under the manufacturing conditions of Example 1, when the temperature of the backup roll was 80 ° C., the embossed sheet was poorly peeled from the backup roll, resulting in poor adhesion with the embossing roll. However, due to insufficient cooling of the sheet, a uniform uneven shape could not be obtained, the aesthetics was unsatisfactory, and the surface glossiness was partially changed greatly.

(Comparative Example 2) When molded under the same manufacturing conditions as in Example 1 except that the temperature of the embossed sheet separated from the embossing roll was set to about 90 to 100 ° C, the center line average roughness of the sheet surface was 2 µm. However, the uneven shape was insufficient, the surface gloss was 8 to 15%, and the fingerprint resistance was deteriorated. Moreover, the sheet thickness is as thin as 0.19 mm, and the thickness uniformity is poor.

(Comparative Example 3) The temperature of the heated sheet was set to 1
When molded under the same manufacturing conditions as in Example 1 except that the temperature was set to 10 ° C (soft temperature + 40 ° C), the thermoplastic resin sheet had a thickness of
The thickness distribution was uniform at 0.2 mm, but the center line average roughness of the thermoplastic resin sheet surface was 0.5 to 2 μm, and the uneven shape was insufficient.

(Comparative Example 4) The temperature of the heated sheet was set to 2
When molding was carried out under the same manufacturing conditions as in Example 1 except that the temperature was set to 40 ° C. (soft temperature + 170 ° C.), the peelability from the preheating roll before pressing was lowered, and stable manufacturing could not be performed.

(Test method) Crushberg flexible temperature: In accordance with JIS K 6734. -Glossiness: In accordance with JIS Z 8741, light emitting angle and light receiving angle
Measured at 60 °. -Center line average roughness: in accordance with JIS B 0601. -Fingerprint resistance: A small amount of artificial sweat made according to JIS L 0848 was attached to the index finger, and the test piece was pressure-bonded with a load of 300 g, and then the degree of conspicuity of the fingerprint was visually determined. The criteria for fingerprint resistance are as follows. Good: At first glance, no fingerprints were found under the light of 500 lux. Deterioration: At first glance, fingerprints were found under the light of 500 lux.

[0019]

According to the present invention, there is no need for a cooling roll for cooling the embossed sheet separated from the embossing roll, the embossed uneven shape of the embossed sheet is not changed, and the embossed sheet is stable and has a uniform thickness. Enables continuous production of sheets. Further, it is a manufacturing method which is extremely effective and excellent in productivity for manufacturing a product having a uniform sheet thickness distribution having a low glossiness, fingerprint resistance and appropriate flexibility like a sheet for a floppy disk jacket.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of a method for manufacturing an embossed sheet of the present invention.

[Explanation of symbols]

1 sheet 3 preheating roll, 4 heating heater 5 backup roll, 6 backup roll surface cooling roll 7 embossing roll, 8 peeling roll 9 cutter, 10 products (embossing sheet)

Claims (1)

[Claims] 1. A method for producing an embossed sheet by supplying a preformed thermoplastic resin sheet to an embossing roll, wherein the thermoplastic resin sheet heated to a temperature 50 to 150 ° C. higher than the Crushberg softening temperature is embossed. Crush Berg of the roll and the thermoplastic resin sheet Pressed and cooled by a backup roll kept at a soft temperature or lower,
A method for manufacturing an embossed sheet, which comprises cooling the temperature of the embossed sheet peeled from the embossing roll to a Crushberg flexible temperature plus 15 ° C or less.