CN1064985C - Preparation method of polyvinyl chloride soft transparent adhesive tape without streamline marks and dents on the surface - Google Patents

Abstract

The invention provides a method for preparing a polyvinyl chloride soft transparent adhesive tape without surface flow marks and dents, which can improve the quality of the polyvinyl chloride soft transparent adhesive tape at high production rate and has obvious difference from the prior common polyvinyl chloride soft transparent adhesive tape with the surface flow marks and dents. In the preparation method, hot melt polyvinyl chloride adhesive plaster which is calendered into specified thickness by a calender is rapidly cooled and shaped by using water as a direct medium, then enters a cooling wheel set for full cooling through a flow of a dewatering mechanism, the temperature of the adhesive plaster is raised to 30-85 ℃, and 1-8 kg/cm of adhesive plaster is added²And (3) pressure coiling to obtain the flat and uniform polyvinyl chloride adhesive tape with good transparency and no flow line mark.

Description

The preparation method of polyvinyl chloride soft transparent adhesive tape without streamline marks and dents on the surface

The known polyvinyl chloride transparent adhesive tape process is to fully gel the raw materials through a mixer, a 10,000-horsepower machine, a roller machine, and an extruder, and then send them into a calender to adjust the thickness, and then pass through a plurality of heating or cooling out of the calender. The wheel set and the cooling wheel set with cold water make it fully shaped, and then coil the finished product.

1. The known method is the above process. Because the cooling is gradual, the rubber is cooled from a molten high temperature to normal temperature. During the cooling process, the semi-fixed rubber is still considerably extended, and the fluidity of its molecules has changed. Poor, forming linear streaks with poor flow.

2. In the above-mentioned known method, when the finished product is wound up at high speed, a large amount of air will be involved in the tape layer, which will gather into comprehensive air bubbles for a long time, causing the tape to have dents formed by the air bubbles after unfolding.

The present invention relates to the preparation method of polyvinyl chloride soft transparent adhesive tape without streamline marks and dents on the surface, and its main special steps are:

1. In the present invention, the melted and softened polyvinyl chloride rubber is gradually rolled to the required thickness from the calender, and then enters the temperature-controlled water bath mechanism (20-85°C) for rapid cooling and finalization, so that the polyvinyl chloride produces partial crystallization effect , to achieve good transparency, so that the rubber material instantly forms a uniform and stable elastomer from the molten state and reaches a state without streamline marks on the surface.

2. After the water bath mechanism, the surface of the elastic adhesive tape has a large amount of water. The present invention uses an extrusion mechanism composed of more than one set of soft rubber and metal wheels or cooperates with drainage equipment such as scrapers, air knives, and vacuum suction to remove the water. Rapid removal increases yield.

3. After the second step, the present invention heats the adhesive cloth to 40-150°C through the heating roller covered with water-absorbing material, eliminates residual moisture and stress, heats the adhesive cloth to a temperature of 30-85°C, and then heats the adhesive cloth to a temperature of 30-85°C. A pressure of 8kg/cm ² is applied to the surface of the coiled finished product to prevent air from being involved so that the surface of the tape is flat and without dents... (If it is coiled in a normal way, the air will enter between the layers of the tape, resulting in dents on the surface of the tape over time )…….

Fig. 1 is the manufacturing process of known polyvinyl chloride transparent adhesive tape, and it is described as follows: Calender 1, lead-out wheel group 2, cooling wheel group 3, coiler 4; PVC powder, plasticizer, stabilizer etc. according to designation After the formula ratio is mixed, it is sent to the 10,000-horsepower machine and the roller machine (A, B), so that it is fully melted and gelled, and then sent to the calender, gradually rolled to the target thickness, and then exits the calender and enters the pull-out wheel (heating or Cooling) for preliminary shaping, then enter the cooling wheel group (internal chilled water or cooling water) to fully cool and shape, and then enter the coiler to coil into finished products.

Fig. 2 is an improved process of the present invention, which is described as follows:

Calender 1, water bath mechanism 2;

Water removal mechanism (including extrusion wheel and water removal wheel or scraper, air knife, vacuum suction equipment) 3;

Cooling wheel set 4, coiling wheel set 5.

After mixing PVC powder, plasticizer, stabilizer and other raw materials with a specified formula, the PVC batch is fully gelled and melted through a high-temperature 10,000-horsepower machine, a roller machine (or an extruder), and then sent to a calender. By controlling the gap between the wheels of the calender, the softened and flat state of the desired thickness can be obtained.

After the above process, a flat high-temperature (160-190°C) polyvinyl chloride film is obtained. After passing through the water bath mechanism 2 in Figure 2, the water temperature is controlled at 20-85°C, so that the film is rapidly cooled and shaped, and a part of the crystal is clear and transparent. tape. If the temperature is not controlled, the amount of water brought up will affect the efficiency and produce streamlines, resulting in poor quality.

The present invention passes through the dewatering mechanism after the water bath mechanism 2, and this mechanism adopts a squeeze wheel combined with a metal wheel and a rubber wheel, and uses idler wheels, scrapers, air knives, water suction wheels, etc. Contains only a small amount of water; without this mechanism, the water in the water bath will be brought into the back-end process with the tape, affecting the quality and efficiency.

The present invention adopts the cold and hot wheel set 4 after the dewatering mechanism 3. This wheel set includes a cooling wheel (cooling water is passed through the wheel), a heating wheel set (40-150° C.), and the surface of the metal wheel is covered with cloth. Water-absorbing materials, while the known cooling wheel is chilled water or cooling water in the wheel; the cooling wheel set of the present invention has the functions of removing water, eliminating pressure, and controlling the temperature before the adhesive tape is taken up, which is different from the known method.

The present invention enters the coiling wheel group 5 after the cooling wheel group 4, controls the appropriate adhesive tape temperature (30-85°C) by the cooling wheel, and applies an appropriate pressure (1-8kg/cm ² ) on the coiled finished product to ensure Prevents air from being trapped for a dent-free and smooth glossy finish.

A brief description of the attached drawings of the application is as follows:

Fig. 1 is known polyvinyl chloride transparent adhesive tape manufacturing process device figure, explains as follows:

1. Calender;

2. Pull out wheel set;

3. cooling wheel set;

4. Finished coiler.

Fig. 2 is the device diagram of the improved formula process of the inventive method, and description is as follows:

1. Calender;

2. water bath mechanism;

3. Water removal mechanism (including extrusion wheel and water removal wheel or scraper, air knife, vacuum suction equipment);

4. cooling wheel set;

5. take-up wheel set;

Comparative example: (known)

To produce transparent polyvinyl chloride adhesive tape with a thickness of 0.2mm and a softness of 40PHR (resin per percent weight), the formula is:

PVC(P=1250) 100

DOP (dioctyl phthalate) 40

Barium zinc stearate stabilizer 2-4

Mix in a high-speed mixer for 5 minutes, and then put it into a 10,000-horsepower machine to squeeze the material until gelatinization is completed. The material temperature is (160-180°C), and then enter the roller machine (A, B), and the material temperature is controlled at 160-180°C. , and enter the cooling wheel group (usually through cold water) to cool and shape, and get the known polyvinyl chloride transparent adhesive tape after coiling; the most difficult shortcoming to overcome at present is the streamlined dent.

Example 1:

To produce a product with a thickness of 0.2 mm and a softness of 40 PHR, its formula and the conditions of the preceding process up to the calender 1 are the same as those of the comparative example, and the material with a controlled thickness rolled out by the calender is introduced into the water bath mechanism (20~ 85°C) to cool to make it partly crystallized and shaped, and then enter the pressurized (1-6kg/cm ² ) extrusion wheel set (1-3 groups) composed of rubber wheels and metal wheels, and cooperate with idler wheels, removal Water, scrapers, air knives, vacuum water absorption equipment and other necessary dewatering machinery, then enter the cooling wheel group (usually warm and cold water inside), and the heating wheel group (wheel surface 40-150°C) lined with water-absorbing material to remove moisture And control the temperature of the tape to 30-85°C and enter the coiling machine (linear speed 60±10 m/min), and take it up with a pressure of 1-8kg/ ^cm2 to obtain a transparent tape without streamline marks and dents.

Example 2:

To produce a transparent adhesive sheet with a thickness of 0.5 mm and a softness of 40 PHR, the production formula and the process before the calender are the same as those of the comparative example, except for the thickness controlled by the calender.

The process of raw materials entering the water bath mechanism (20-85°C), water removal mechanism, cooling wheel group, heating wheel group, and tape coiling temperature and pressure are the same as in Example 1, except that the speed of coiling the finished product is controlled at 15-30m/min. After coiling, the finished PVC tape with no streamlines and dents and a thickness of 0.5mm can be obtained.

Claims (5)

1. A method for preparing a thermoplastic polyvinyl chloride soft transparent adhesive tape without streamline marks and dents on the surface, comprising: a. The formation of thermoplastic soft transparent adhesive tape without streamline marks, this step includes rapidly cooling the rubber material through a water bath mechanism after being calendered by the wheel surface of the calender; b. Use water removal equipment to remove the moisture attached to the surface of the adhesive tape after the water bath; c. The heating and drying section is arranged in the cooling wheel group, and the cooling and reheating are combined to keep the adhesive tape at 30-85°C before coiling; d. Take up the adhesive tape under the condition that the temperature of the adhesive cloth is 30-85°C and the adhesive cloth is given a pressure of 1-8kg/cm ² . 2. The preparation method according to claim 1, wherein the water temperature is controlled between 20-85° C. in the water-bath mechanism. 3. The method according to claim 1, wherein said dewatering equipment is extrusion wheel and/or electroplating idler, scraper, air knife, vacuum suction equipment. 4. The method according to claim 1, wherein the wheel surface temperature of the heating and drying section of the cooling wheel group is 40-150° C., and the wheel surface is covered with a water-absorbing material. 5. The manufacturing method according to claim 1, wherein during the coiling process, a pressure wheel is arranged above the finished product or both ends of the finished product reel are pressurized and coiled.

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