JPH0453172B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for manufacturing an embossed sheet made of thermoplastic synthetic resin, and in particular, an effective method for manufacturing a sheet with a fine and deep wrinkle pattern that does not disappear even when reheated. Regarding. [Conventional technology] Usually, embossed sheets of thermoplastic synthetic resin are
The embossing roll on which the desired uneven pattern has been formed is maintained at a predetermined heating temperature, and the heated synthetic resin sheet is continuously fed between the embossing roll and the back-up roll to perform press embossing, and then cooled. Manufactured by Embossing of an embossed sheet, which is widely used as a resin sheet whose surface is less conspicuous with dirt and whose imprint marks are less conspicuous, is generally carried out by the method described above. [Problems to be solved by the invention] Resin sheets are usually used by processing the sheet into a bag shape through secondary forming such as folding.
From a practical point of view, the outer surface of the bag is formed into a fine continuous grained pattern with a matte finish. This matte emboss reduces gloss and prevents light reflection, giving it a sense of elegance. It also significantly improves fingerprint and scratch resistance compared to smooth surfaces, making it desirable from a handling standpoint and widely used. has been done.
In addition, since this embossing process is performed on a long sheet, during the operations up to jacket formation, for example, during thermal processing such as thermal welding of the nonwoven fabric to the inner surface, and thermal bending and welding of the flap part, heating is required. Unavoidable inconveniences arise in that the processed area becomes grainy and the unevenness disappears or becomes smaller and becomes smoother, forming a mottled pattern, resulting in a significant deterioration in appearance and a significant loss in commercial value. The present invention aims to provide an embossed sheet with deep wrinkles and unevenness without such inconvenience. [Means for Solving the Problem] In order to solve the above-mentioned technical problems, the present inventor conducted many experimental studies and found a practically desirable and effective method. That is, the present invention provides a method for manufacturing an embossed sheet by continuously feeding a thermoplastic synthetic resin sheet to an embossing roll, in which the sheet is maintained at a temperature 20 to 120°C higher than the glass transition temperature Tg of the resin. It is supplied between the embossing roll and the back-up roll to perform pressure embossing.
The crimped embossed sheet pressed onto the surface of the embossing roll is further pressed with one or more other back-up rolls before being separated from the embossing roll, and then peeled off from the roll and rapidly cooled. A method for manufacturing a thermoplastic synthetic resin embossed sheet is provided. The thermoplastic synthetic resin used in the present invention is not particularly limited as long as it has appropriate hardness and strength for the jacket of a floppy disk, but vinyl chloride resins are industrially advantageously employed. Preferably, a homopolymer of vinyl chloride is used without adding a plasticizer, but those to which a small amount of plasticizer is added or copolymers or blends with other polymerizable monomers can also be advantageously used. In addition, commonly known opaque formulations can be advantageously adopted as compound formulations for sheet formation.
In that case, desired coloring can be achieved using various pigments, but the industrially advantageous pigment is carbon, which has extremely excellent light blocking properties. Furthermore, in the present invention, the temperature of the embossing roll that is heated and maintained is within a temperature range of 20 to 120°C higher than the glass transition temperature of the thermoplastic synthetic resin constituting the sheet to be embossed, and lower than 20°C. Then, the emboss will be insufficient,
If the temperature is higher than 120°C, the melt viscosity of the sheet itself decreases, making it difficult to peel it off from the embossing roll, which is not preferable. A preferred temperature range is about 30 to 110°C above the glass transition temperature of the resin.
For example, polyvinyl chloride (Tg
(approximately 75°C to 85°C) and typically 110°C to 190°C. On the other hand, as the embossing roll, one in which the surface of a metal roll is corroded to form a uniform satin matte surface with a depth of 20 to 60 μm of unevenness is advantageously used. A back-up roll for pressing and embossing sheets is a rubber roll in which a heat-resistant rubber layer is adhered to the surface of a metal core roll, and heat-resistant silicone rubber is conveniently used as the rubber material. It will be done. The sheet to be embossed is preferably preheated, for example by a preheating drum, to a temperature close to the embossing roll temperature, guided to the surface of the embossing roll, and first pressed with a first back-up roll to be embossed. In the present invention,
It is important to press the crimped sheet pressed onto the surface of the embossing roll with one or more other back-up rolls before separating it from the embossing roll. It is characteristic that the material is cooled as quickly as possible after being removed from the embossing roll. The number of additional press embossing rolls is preferably as large as possible, but in practice, the number is one or two. The cooling is preferably quenched by a chill roll cooled to below the glass transition temperature of the synthetic resin of the sheet. [Example] A compound of the following composition was made into a sheet with a thickness of 0.25 mm by a calendering method, and an embossed sheet was produced using a long sheet wound up under various embossing conditions. Composition (parts by weight) Polyvinyl chloride (p=800) 100 MBS resin (Kane Ace B-22 manufactured by Kanebuchi Kagaku Co., Ltd.) 10 Tribasic lead sulfate 4 Calcium stearate 0.5 D0P 2 Carbon black 2 The above polyvinyl chloride The glass transition temperature of
It is 83℃. As an embossing device, one having the arrangement shown in FIG. 1 of the attached drawings was used. As shown in the figure, roll 1
The sheet 2 pulled out from the sheet 2 passes through a guide roll 3 and is heated in contact with a metal heating roll 5 equipped with an infrastructure heater cover 4 over approximately half the circumference. The heated sheet is then guided to an embossing roll 6, and a back-up roll 7 near the contact area.
is pressed, and the first embossing process is performed. Furthermore, the sheet 2 in contact with the embossing roll 6
After being pressed again by the back-up roll 8, it is removed from the embossing roll 6, cooled by metal cooling rolls 9, 10, and 11, and then rolled onto the take-up roll 1.
It is configured to be wound up in two steps. Note that the surface of the embossing roll 6 is
It is a satin carving with a depth of 200μm and unevenness of 50μm. Examples 1 to 3 and Comparative Examples 1 to 6 Various embossed sheets were created by changing the operating conditions of the following parts of the above apparatus. A: Temperature of the sheet introduced between rolls 6 and 7 (°C) B: Emboss roll 6
Temperature C of (heating medium circulation heating method): Pressure force of roll 8 against 6
(ton/1000m width) D: Temperature of cooling roll 9 (hot water circulation method) (℃) E: Cooling roll 10
(Hot water circulation system) temperature (°C) F: Sheet transport speed (m/min) In all experiments, the pressing force of the back-up roll 7 against the embossing roll 6 was
Fixed to 2ton/1000mm width, final cooling roll 11
was kept at a constant temperature of 60°C in all cases. Table 1 summarizes the operating conditions in each experiment and the various measurement results for each embossed sheet obtained. In the comparative example in the table, the backup roll 8 was moved and operated without being pressed. The test methods for measuring various physical properties are as follows. Test method Maximum surface roughness: Maximum height in JIS B 0601. Glossiness: JIS Z 8741 Light emitting/receiving angle 60° Scratch resistance: JIS K 6902 Using a Clemens type scratch hardness tester, visually judge the degree of scratches caused by a 30g load of a saphire needle. Fingerprint resistance: A small amount of a commercially available men's hair conditioner (Kanebo Co., Ltd. Vulcan Hair Liquid) is applied to a human index finger, and after being pressed against a test piece with a constant load of 300g, the degree of fingerprint conspicuousness is visually determined.
The evaluation criteria for determining fingerprint resistance are as follows. ×... Scratches and fingerprints are clearly visible at first glance under 500 lux light △... Scratches and fingerprints are clearly visible when carefully examined under 500 lux light ○... ...If you look very carefully under 500 lux light, you can barely see scratches or fingerprints. ◎...Even if you look very carefully under 500 lux light, you can barely see any scratches or fingerprints. Unacceptable grain return test: Place the test piece in a constant temperature bath at the specified temperature, take it out after 20 minutes, cool it to room temperature, and measure the maximum surface roughness.

【table】

〔Effect of the invention〕

According to the method of the present invention, it is possible to sufficiently deepen the embossing depth on the sheet surface using one embossing roll, and also to achieve beautiful embossing with excellent resistance to shrinkage due to heat, good scratch resistance and fingerprint resistance. Sheets can be manufactured with high productivity.

[Brief explanation of the drawing]

FIG. 1 is a schematic layout of an example of an apparatus for carrying out the method of the present invention. Symbols in the figure: 2... sheet, 5... heating roll, 6... embossing roll, 7, 8... back up roll, 9, 10, 11... cooling roll.

Claims (1)

[Claims] 1. A method for producing an embossed sheet by continuously feeding a thermoplastic synthetic sheet to an embossing roll, in which the sheet is heated to a temperature 20 to 120°C higher than the glass transition temperature (Tg) of the resin. The embossed sheet is fed between the held embossing roll and the back-up roll for pressure embossing, and the crimped embossed sheet is pressed onto the surface of the embossing roll.
Before pulling it away from the embossing roll, add another one.
1. A method for producing an embossed thermoplastic synthetic resin sheet, which comprises pressing with a back-up roll or more, then peeling from the embossing roll and rapidly cooling. 2. The method according to claim 1, wherein the thermoplastic synthetic resin is a hard vinyl chloride resin.