KR100285526B1 - Calendering Process for Producing Thermoplastic Rubber Films or Sheets and the Products Thereof - Google Patents

Abstract

The present invention discloses a process for producing thermoplastic rubber (TPR) film and laminated TPR film and TPR leather of fabric. In particular, the present invention relates to a calendering method for producing a TPR film and TPR leather by blending a TPR composition suitable for calendering and selecting appropriate operating conditions. TPRs suitable for use in the present invention include those with a melt index (180 ° C.) of greater than one. TPR alone or blended with other resins is calendered, to which lubricants such as zinc stearate and polyethylene wax, optionally antioxidants and UV absorbers are added. The TPR composition rolled by an inverted L-shaped calender consisting of four calender rolls at a temperature of 120-170 ° C. has a melt viscosity in the range of 20000-80000 poise.

Description

Calendering Process for Producing Thermoplastic Rubber Films or Sheets and the Products Thereof}

The present invention relates to a calendering method of thermoplastic rubber (TPR) material. More specifically, the present invention relates to formulating a TPR composition suitable for the TPR calendering method and selecting appropriate operating conditions. Calendering is a continuous thermoforming method that forms sheets or films from thermoplastic materials that are softened by heat. Calendering is well known in the art and is described here ("DI Marshall's" Processing of Thermoplastic Materials ", EC Bernhardt, Reinhold Publishing Corporation, New York (1962) and FH Ancker and HJ Ruther ford," The Encyclopedia of Engineering Materials "). and Processes, '' HR Clanser, Reinhold Publishing Corporation, New York (1963).

Background

A feature of the thermoplastic material is that it can soften when heated and return to its original solid state when cooled. These materials are usually prepared in pellet form, but powders may also be used. Thermoplastic rubber (TPR) pellets, which were originally introduced in the extrusion process, can be used in the injection process, but have not been used so far in the calendering process. Melt-flowing properties of thermoplastic materials are of great importance in extrusion and injection processing. In the injection processing method, a melting thermoplastic composition is put into a mold. In the extrusion process, the thermoplastic composition dissolved through the T die is pressed and cast on a molding roller. A technically important point in calendering is to control the melt viscosmetric strength of the thermoplastic composition so that the thermoplastic composition does not adhere to the calender rolls and can be extended as desired. The melt viscosity method strength of the thermoplastic composition is tailored by adjusting the operating conditions of the calendering method and the recipe of the thermoplastic composition.

According to the injection operation, the materials of TPR pellets, colored pigments, stabilizers and lubricants are combined and then the blending mixture is placed in the hopper of the injection molding machine. Increasing the temperature of the mixture to an appropriate range (170 ° C.-250 ° C.) according to its compounding formula will result in a good flow mixture. The dissolution mixture is then injected into the mold by a movable piston with a screw structure. After the mold has cooled, individual articles such as TPR shoe soles are formed as a replacement for conventional rubber shoe soles.

Various extruded TPR products are far worse than various injection molded TPR products. TPR powder, colored pigments, stabilizers and lubricants are mixed and then the mixture is placed in the hopper of the extrusion machine. There is a hotter band around the chamber of the extruder and the mixture is heated to a suitable operating temperature range (170 ° C.-250 ° C.) by a temperature profile consisting of 3-5 steps. There is also a screw in the chamber of the extruder that has been specially designed to provide metering, blending, and transport functions in three different sectors, to ensure that the mixture is in proper dissolution. The solubility mixture thus produced is filtered and further mixed by a static mixer to form a homogeneous mixture with good flow properties. It is then cast on a molding roller having an electroplating surface or a protruding surface that is pressed and polished through a T-die. After cooling, a TPR product is obtained which is extended by the molding roller.

In general, injection molding has been widely applied to TPR materials. Calendering methods have not been applied to TPR materials because of their melt viscosity method properties.

In the present invention, thermoplastic rubber (TPR) such as styrene-butadiene-styrene block copolymer (SBS) and styrene-ethylene butadiene-styrene block copolymer (SEBS) having a melt viscosity in the range of 20000 to 80000 poises is calendered. Used for In general, the melt viscosity of a TPR material with a melt index (MI) (180 ° C.) of greater than 1 is less than 20000 poise at a temperature of 170 ° C.-200 ° C. Melt viscosities less than 20000 poise are not suitable for calendering because they cause the dissolved TPR material and calender roll to stick together. The melt viscosity of the TPR material with a MI (180 ° C.) of less than 1 is higher than 80000 poise at a temperature of 150 ° C.-170 ° C. Such melt viscosities (> 80000 poise) are not suitable for application to calendering processes because of the difficulty of TPR material flow under these viscous conditions. If the calendering temperature is higher than 170 ° C, the TPR material will not be usable because it will be degraded by the high temperature.

Moreover, SBS (Styrene-Butadiene-Styrene Block Copolymer), SEBS (Styrene-Ethylene Butadiene-Styrene Block Copolymer) and its blending mixtures are so low in viscosity that they cannot be applied to calendering in the dissolved state.

The present invention solves the problems existing in the process of calendering thermoplastic rubbers by selecting the appropriate TPR MI, the appropriate additives, and the appropriate operating conditions.

1 is a schematic flow diagram illustrating a method of making a thermoplastic rubber (TPR) film in accordance with a preferred embodiment of the present invention.

FIG. 2 is a schematic flow diagram illustrating a method of making a laminated TPR film and TPR leather of a cloth, in accordance with another preferred embodiment of the present invention, where FIG. 2A is a calendering sector, FIG. 2B is a surface treatment sector, 2C shows an embossing sector.

Explanation of symbols for main parts of the drawings

1: high speed mixer 2: banbury 3: rolling mill

4: strainer 5: calendar 6, 16: embossing roller

7, 17: cooling roller 8, 12, 18: winder

9, 13: Semifinished product feed roll 10: Pick-up roller 11: Oven

14: preheat roller 15: heater 60: cloth feed roll

1 is one of the preferred embodiments of the present invention. 100 parts by weight of TPR (MI (180 ° C.)> 1) or a blend of TPR and thermoplastic polymer, 0-40 per hundred parts of resin (PHR) pigment or color masterbatch, 0.2-2.0 PHR zinc stearate A mixture consisting of 0.05-1.0 PHR polyethylene wax (PE-WAX), 0.3-2.5 PHR antioxidant and 0.3-2.5 PHR UV absorber was mixed by high speed mixer (1). The resulting mixture was removed in a high speed mixer (1) and milled in Banbury (2) at a temperature of 110-150 ° C. for 2-6 minutes to form a gel-like block. The block is subjected to an advanced-mixing treatment using a rolling mill 3 at a temperature of 110-170 ° C. to form a more homogeneous, gelatinous mixture, which then removes impurities. Was supplied to the strainer 4 in order to. The mixture from the strainer 4 was fed to a standard inverted L-shaped calender 5 consisting of four calender rolls of substantially the same diameter. The temperature of the calender roll 5 was controlled in the range of 120 ° C.-170 ° C. so that the rolled composition was in the proper viscosity method state (20000-80000 poise). The rotational speed of the calender roll 5 to form a sheet product of a predetermined thickness is such that the front calender roll: upper calender roll: center calender: lower calender roll is 1: (1.25-1.35): (1.28-1.38): (1.31-1.41 Controllability).

In addition, the rolled sheet product is embossed by the embossing roller 6 at a temperature of 10 ° C.-60 ° C., cooled by a cooling roller 7 at a temperature of 10 ° C.-60 ° C., and wound on the winder 8. It was. In the process of FIG. 1, the Banbury 2 can be replaced with a kneading machine or a device having a similar function. The rolling mill 3 can be replaced by a planetary extruder or other type of extruder with similar mixing performance.

Another object of the present invention is to provide a new and improved calendering process for producing TPR leather, wherein the TPR film and pretreated fabric are laminated before entering the embossing step. The pretreated fabric is made by coating the cloth with a layer of low molecular weight TPR solution or PU adhesive that will enhance the adhesive strength between the cloth and the TPR film. A suitable method of making TPR leather according to the invention is shown in Figures 2A, 2B, 2C. Parts of the same kind are designated by the same numbers as in FIG. As in FIG. 2A, pretreated fabric was taken on the cloth feed roll 60 and laminated with the TPR film of the calender roll 5 by an embossing roller 6. The laminated product was cooled by the chill roller 7 and then wound on the winder 8. The cloth used in the present invention may be a non-woven cloth, a weave fabric or a knitting cloth. The semiproduct on the winder 8 was then subjected to a surface treatment as in FIG. 2B, wherein the surface treatment method removes the semifinished product from the semifinished feed roll 9 and polyurethanes its TPR surface on the pickup roller 10. After coating with a (PU) -based surface treatment solution, it was heated in an oven 11 and wound in a winder 12.

The semifinished product wound on the winder 12 was then embossed as in FIG. 2C where the semifinished product was taken out of the semifinished feed roll 13 and heated on the preheat roller 14 and by the heater 15. The TPR surface of the heated semifinished product was embossed by the embossing roller 16 to form a texture, cooled by the cooling roller 17 to fix the texture, and wound on the winder 18.

In the present invention, TPR (SBS or SEBS) with a MI (180 ° C.) of 1-50 was used to produce thermoplastic rubber films by calendering.

Pigment or PE based color masterbatches in pellet or powder form with a suitable color of 0-40 PHR can be used in the TPR film produced by the present invention. Lubricants, zinc stearate or PE-WAX are used to enhance the peelability of thermoplastic rubber in calender rollers and also to reduce the adhesion between TPR film and calender rolls. Suitable amounts of zinc stearate for use in the present invention are in the range of 0.2 to 2.0 PHR and PE-WAX in the range of 0.05 to 1.0 PHR.

TPR films used outdoors are exposed to harmful solar radiation that can cause discoloration, brittleness and breakage of TPR materials. TPR films can be protected from solar radiation by the addition of antioxidants and UV absorbers, each capable of absorbing harmful UV radiation in the presence of oxygen and protecting the plastic from automatic oxidation. In preparation for various environmental conditions, 0.3-2.5 PHR antioxidant and 0.3-2.5 PHR UV absorber are used in the present invention.

The invention is further illustrated by the following examples.

Example 1: Preparation of 0.25 mm TPR Film

Using a high speed mixer, 100 parts by weight of mixed resin pellets (TPR (MI (180 ° C.) = 4): LLDPE (MI = 2.8) = 1: 1 to 9: 1), 0.2-2.0 PHR zinc stearate, A mixture consisting of 0.05-1.0 PHR PE-WAX, 0.5-5.0 PHR color masterbatch and 0.3-2.5 PHR antioxidant was prepared (FIG. 1 (1)). The resulting mixture was removed in a high speed mixer and milled in banbury (FIG. 1 (2)) for 2-6 minutes at a temperature of 110-150 ° C. The homogeneous gel-like block from Banbury was subjected to an advanced mixing step at a temperature of 110 ° C.-170 ° C. with a rolling mill (FIG. 1 (3)) to obtain a more homogeneous mixture. The mixture is then fed to a strainer (FIG. 1 (4)) to remove impurities and to enter an inverted L-shaped calender (FIG. 1 (5)) consisting of four calender rolls. The rotational speed of the calender roll was also controlled by the rotational speed ratio of front calender roll: upper calender roll: center calender roll: lower calender roll = 1: (1.25-1.35): (1.28-1.38): (1.31-1.41). The rolled film was removed from the calender roll with a stress suitable to keep the rolled film flat.

Further, the rolled film was embossed by an embossing roller (Fig. 1 (6)) at a temperature of 10 ° C.-60 ° C. and a cooling roller ((7) of Fig. 1) at a temperature of 10 ° C.-60 ° C. (480 m / mψ × 15pcs). A uniform rolled film was observed and wound up with a winder (8 in Fig. 1).

Example 2: Preparation of 1.6 m / m TPR Leather Cloth

100 parts by weight of TPR pellet (MI (180 ° C.) = 4), 0.2-2.0 PHR zinc stearate, 0.05-1.0 PHR PE-WAX, 0.5-5.0 PHR color masterbatch, 0.3-2.5 PHR antioxidant and 0.3-2.5 A mixture consisting of PHR UV absorbers was prepared by a high speed mixer. The resulting mixture was removed in a high speed mixer and ground in Banbury for 2-6 minutes at a temperature of 110 ° C-150 ° C. The homogeneous gel-shaped block thus made was subjected to an advanced mixing procedure at a temperature of 110 ° C.-170 ° C. with a rolling mill to obtain a more homogeneous, gelatinous mixture. The mixture was then fed to an inverted L-shaped calendar consisting of four calender rolls. The temperatures of the calender rolls were controlled such that the temperatures of the front calender roll, the top calender, the center calender and the bottom calender roll were 145 ° C-165 ° C, 135 ° C-155 ° C, 125 ° C-145 ° C and 125 ° C-145 ° C, respectively. Moreover, the rotation speed of the calender roll was controlled by the rotation speed ratio whose front calendar roll: upper calender roll: center calender roll: lower calender roll is 1: (1.25-1.35): (1.28-1.38): (1.31-1.41). The pretreated nonwoven fabric was laminated together with the film of the calender roll by an embossing roller (6 in FIG. 2A). Pretreated nonwovens were prepared by coating the nonwovens with a layer of low molecular weight TPR solution or PU adhesive to improve adhesion between the cloth and the TPR film. The laminated product was cooled by a chill roller, coated with a PU-based surface treatment solution, and then heated to dry. The surface treated semifinished product was preheated by a preheat roller (14 in FIG. 2C) at 100-140 ° C. and by a heater (15 in FIG. 2C) at 130-170 ° C. and then embossed roller at 10-60 ° C. After embossing by (16 in FIG. 2C), it was cooled by the cooling roller (17 in FIG. 2C) at 10-60 degreeC. The desired texture was thus formed and fixed to the TPR surface of the surface treated laminated TPR / cloth article wound on a winder (18 in FIG. 2C) as a product of TPR leather.

Included in the above.

Claims (1)

A calendering method for producing a thermoplastic rubber (TPR) film or sheet comprising calendering a TPR or their polymer blend based composition to form a film or sheet using an inverted L-shaped calender composed of four calender rolls. , The composition was prepared using a high speed mixer, 100 parts by weight of TPR pellets with a melt index (180 ° C.) of TPR or mixed resin pellets of TPR and thermoplastic material, 0-40 PHR color masterbatch, 0.2-2.0 PHR zinc Prepared by mixing stearate, 0.05-1.0 PHR PE-WAX lubricant, 0.3-2.5 PHR antioxidant and 0-2.5 PHR UV absorber; The resulting mixture is then removed in a high speed mixer and milled in Banbury for 2-6 minutes at a temperature of 110 ° C.-150 ° C. to form gel shaped blocks; The gel-shaped block is removed in banbury and the block is subjected to an advanced mixing procedure using a rolling mill at a temperature of 110 ° C.-170 ° C. to obtain a more homogeneous and gelatinous mixture; The more homogeneous, gelatinous mixture from the rolling mill is then fed to the strainer to remove impurities before entering the inverted L-shaped calendar, in which the front calender roll, upper calender roll, center calender roll and lower calender roll The temperatures of 145 ° C.-165 ° C., 135 ° C.-155 ° C., 125 ° C.-145 ° C., and 125 ° C.-145 ° C., respectively, and the rotational speeds of the calender rolls are: front calender rolls: upper calender rolls: center calender rolls: lower calenders The roll is controlled at a rotational speed ratio of 1: 1.25-1.35: 1.28-1.38: 1.31-1.41; The film or sheet made from the calender is embossed by an embossing roller at a temperature of 10 ° C.-60 ° C., cooled by a cooling roller at a temperature of 10 ° C.-60 ° C. and then wound on a winder. TPR) Calendering method for producing films or sheets.