RU2779275C1 - Method for producing polyvinyl chloride decorative film for furniture and vinyl floor coverings with a protective layer - Google Patents

Abstract

FIELD: molded materials production.

SUBSTANCE: invention relates to the production of products or molded materials containing macromolecular substances, and for the production of decorative films for furniture and vinyl flooring covered with a protective layer. The method includes the stage of mixing suspension polyvinyl chloride (PVC), stabilizer, impact strength modifier and processability modifier, the stage of mixing with pigments and/or dyes, the stage of extrusion processing of the composition and film calendering, while one hot and two cold mixers are used at the mixing stages. Suspension polyvinyl chloride, a stabilizer, an impact strength modifier and a processability modifier are fed from the weighing equipment to the hot mixer at low stirrer speeds of 740 rpm. Then intensive mixing is carried out at a speed of 1500 rpm until the temperature of the composition reaches 100-125°C. The hot composition is discharged into one of the cold mixers and the pigments and/or dyes are added with the mixer continuously running at 740 rpm. Water with a temperature of 24-27°C is supplied to the cold mixer jacket and the composition is cooled to a temperature not exceeding 60°C. Before the stage of extrusion processing and calendering, the resulting colored composition is unloaded into an intermediate container.

EFFECT: invention provides an increase in the productivity of the line for producing a film with stable decorative and strength properties.

8 cl, 1 dwg, 1 tbl, 1 ex

Description

Technical field

The invention relates to the field of production of products and molded materials containing macromolecular substances. In particular, the invention relates to the production of a decorative PVC film for furniture and vinyl floor coverings with a protective layer by processing the molding composition: mixing, dyeing and subsequent extrusion, and calendering. If necessary, the film can be stretched in an inline or offline process and thermoformed.

State of the art

Decorative films are obtained from molding material by dyeing and subsequent extrusion through a die or by calendering.

Plasticized and rigid PVC compositions are modified in a known manner by adding various additives to obtain the desired property profile. Known PVC compositions can be heat processed and are suitable for a variety of applications such as packaging, shrink and non-plasticized films. To modify PVC films, a modifier is added to improve impact strength, to improve heat resistance, processing aids to improve machinability and increase plant productivity, softener to improve gelatinization parameters during manufacture, flow improver to improve thermoplasticity and stretchability, matting agent to reduce gloss and the like. The weight fractions of individual additives, depending on the requirements, range from 0.1 to more than 40 wt. %. To improve the flow and stretchability of PVC compositions, vinyl chloride copolymers are preferably used.

From European patent EP 0 172 479 B1, a method for producing a decorative film with a matt and rough surface based on vinyl chloride polymer and fillers is known. In addition, softeners and heat stabilizers are added.

DE 2716853 discloses a process for producing a film which consists of a vinyl chloride polymer, a stabilizer and a softener by calendering with a mixing roller. The impact strength modifier is selected from the group of copolymers of acrylonitrile-butadiene-styrene, methyl methacrylate-butadiene-styrene and methyl methacrylate-

acrylonitrile butadiene styrene.

EP 1 066 339 B1 describes a process for producing a film or sheet from a polyester resin composition by calendering. The resin contains an additive, which is an internal lubricant or anti-skid agent, or a mixture of both. The amount of additives is from 0.01 to 10 wt. % based on the total weight of the resin composition.

In conventional PVC films, polymerization products of acrylonitrile-butadiene-styrene, methyl methacrylate-butadiene-styrene, methyl methacrylate-acrylonitrile-butadiene-styrene, methyl methacrylate and chlorinated polyethylene, polymethyl methacrylate and ethylene-vinyl acetate copolymer as impact-resistant components are used as a modifier, in an amount of 1 up to 20 wt. %, based on the weight of the PVC film. Common softeners for PVC molding compounds from which PVC films are produced are fatty acids, fatty alcohols, fatty acid amides, metal soaps, fatty acid esters with mono- or polyhydric alcohols, esters of dicarboxylic acids with mono- or polyhydric alcohols, esters of fatty acids and dicarboxylic acids with polyhydric alcohols, so-called mixed esters or complex esters, phthalic acid esters with mono- or polyhydric alcohols, or natural or synthetic waxes. The number of softeners is from 0.1 to 2 wt. % based on the total weight of the molding composition. Known heat stabilizers are organotin stabilizers, in particular tin carboxylate, tin mercaptide and tin glycolate. In addition, metallic stabilizers based on calcium, zinc, barium, cadmium, and other metal-free organic stabilizers and inorganic stabilizers such as dihydrotalcite based chlorine scavengers are applicable. The proportion of heat stabilizers is usually from 0.3 to 5 wt. % based on the total weight of the molding composition.

From the molding composition, by extrusion through a die or by calendering, a film or film web is obtained, which can then be processed further, in line and/or offline, for example, by drawing.

PVC compositions are modified in a known manner by adding various additives to obtain the desired property profile. Known PVC compositions can be heat processed and are suitable for a variety of applications such as packaging, shrink and non-plasticized films. To modify PVC films, a modifier is added to improve toughness, to improve heat resistance, processing aids to improve machinability and increase plant productivity, softener to improve gelatinization parameters during manufacture, flow improver to improve thermoplasticity and stretchability, matting agent to reduce gloss and the like. The weight fractions of individual additives, depending on the requirements, range from 0.1 to more than 40 wt. %. To improve the flow and stretchability of PVC compositions, vinyl chloride copolymers are preferably used.

Russian patent RU 2382801 solves the problem of obtaining a film based on polyvinyl chloride or vinyl chloride polymer, which has improved thermoformability, stretchability, ductility, pasteurizability, and reduced optical defects such as spotting, and thereby improved light transmission, color neutrality, light and thermal stability films.

To do this, additives from the group of modifiers, preferably high molecular weight polymers, stabilizers, waxes, anti-caking agents, dyes, plasticizers, processing aids are introduced into the molding mass. Films or film webs according to the invention are produced in such a way that the molding mass is extruded to form an unstretched film or film web with a thickness of 100 µm to 1 mm. This film or film web can be used or additionally stretched in the next process step (in-line and/or offline).

The method for producing a film or film web from a molding composition includes the following steps:

(a) mixing vinyl chloride polymer or polyvinyl chloride in the proportion of 5-94 wt. %, with a K coefficient from 50 to 90, in the form of powder, tablets, granules with additives, the proportion of which is from 2 to 25 wt. % of the molding mass;

(b) adding semi-crystalline or amorphous polyester in the form of powder, tablets or granules, in an amount of from 5 to 90 wt. % of the molding mass;

(c) melting the molding composition obtained according to stages (a) and (b);

(d) extruding the molten molding composition at temperatures from 150 to 250° C. to form a film or film web, and

(e) if necessary, stretching the film or film web in-line or offline to a draw ratio of 1.3 to 7.

Coloring is done by adding pigments and/or dyes.

The known method allows to obtain a film with desired stable properties. However, the technological process is not optimal. So, when switching from the production of one brand of film to another, the equipment is stopped, technological maintenance and cleaning of the production line are carried out for several hours. This process is especially lengthy if the dye or pigment changes. The addition of pigments or dyes in this case is carried out according to the traditional scheme in a hot mixer, followed by feeding the mixture into a cold mixer. The process time due to such stops increases significantly, and additional mixing is required for stable staining.

Statement of the Invention

The present invention is aimed at solving the problem of increasing the productivity of the line for producing decorative films of different grades and colors based on polyvinyl chloride by reducing the number of stops during the change of the recipe. The invention is also directed to obtaining a film for furniture and floor coverings with improved and stable strength and color properties.

The technical result of the present invention is to increase the productivity of the process of obtaining a film with stable decorative and strength properties.

This eliminates the shutdown of equipment for technological maintenance and cleaning, provides a reduction in the time for film production, creates conditions for stable uniform coloring, and ensures the production of a high-strength film.

This technical result is achieved due to the fact that in the method for producing a polyvinyl chloride decorative film, which includes the stage of mixing suspension PVC, stabilizer, impact strength modifier and processability modifier, the stage of mixing the composition obtained at the first stage with pigments and / or dyes, the stage of extrusion processing of the composition and film calendering, one hot and two cold mixers are used at the mixing stages, suspension polyvinyl chloride, a stabilizer, an impact strength modifier and a processability modifier are fed from the weighing equipment to the hot mixer at low stirrer speeds of 740 rpm, then intensive mixing is carried out at speed 1500 rpm until the temperature of the composition reaches 100-125°C, the hot composition is unloaded into one of the cold mixers and pigments and/or dyes are introduced with a constantly running mixer at a speed of 740 rpm, water with a temperature of 24-27°C is fed into the jacket of the cold mixer, the composition is cooled to a temperature below 60°C, and before the stage of extrusion processing and calendering, the resulting colored composition is unloaded into an intermediate container.

The technical result is enhanced by the fact that a hot mixer is used, which is a hopper with a self-cleaning filter, an agitator, a horizontally opening lid, two loading holes and a thermocouple for temperature control, while the lid is equipped with a safety limit switch to stop the mixer motor when the lid is opened, and viewing window.

Two cold mixers are used in the production line.

Each cold mixer is a double-walled hopper equipped with a mixing paddle agitator, lid, inlet and outlet openings and a thermocouple for temperature control, while the lid is hydraulically openable and equipped with a safety switch to stop the agitator when it is opened, and both cold mixers mounted on load cells.

The process is controlled automatically by means of a control system to which mixer motors, safety limit switches, temperature control thermocouples, weighing equipment and load cells are connected.

During operation of the first cold mixer, the second cold mixer is stopped for maintenance.

The transition from one film recipe to another is carried out without stopping the line.

Cold mixers are used alternately.

Description of graphic materials

The essence of the invention and the possibility of solving the problem and achieving the technical result will be more clear from the subsequent description of the method for producing a PVC decorative film with reference to the figures of the accompanying graphic materials, where Fig. L shows a diagram of the mixing stage of the production line for film production.

An exemplary embodiment of the invention

The method is carried out on a production line (figure 1), the equipment of which consists of scales for liquid components 1 and a hopper with weights 2 used to measure the weight of powdered components, a hot mixer 3, two cold mixers 4, which can operate simultaneously or be used alternately , intermediate tank 5 in front of the equipment for extrusion and calendering.

Hot mixer 3 is a hopper with a self-cleaning filter, agitator, horizontally opening lid, two filling holes and a thermocouple for temperature control. The lid is equipped with a safety limit switch to stop the mixer motor when the lid is opened, and a viewing window. The useful total volume of the mixing hopper is 1275 l, the material of the inner walls is stainless steel. The lid is made of polished stainless steel and opens horizontally with a pneumatic cylinder lift system, has a silicone rubber slope and a safety limit switch to stop the motor when the lid is opened. The lid is also equipped with a viewing window, vent and loading connection. The bunker provides up to 7 downloads per hour. Heating temperatures of the mixture of components up to 125°C. A 400 kW variable flow drive motor is used. The mixer shaft rotates on thrust bearings. Thermocouples are installed on the side of the hopper, which provide control of the temperature of the mixture. Thermocouples, a safety switch, a drive motor are connected to the automatic control system 6 of the production line with an electric control cabinet 7, where electrical equipment is located that supplies power to all electronic and electrical components.

Each cold mixer 4 is a double-walled (jacketed) hopper equipped with a mixing paddle, lid, inlet and outlet, temperature control thermocouple and self-cleaning filter. In this case, the lid is made hydraulically openable and is equipped with a safety switch to stop the agitator when the lid is opened. The outlet is equipped with a pneumatic actuated throttle valve and a solenoid valve. The hoppers are mounted on load cells that allow you to control the loading and unloading phases.

The process is controlled automatically by the control system 6, 7, to which mixer motors, safety limit switches, temperature control thermocouples and load cells are connected.

The method is carried out as follows

At the first stage of mixing, weighed suspension polyvinyl chloride (PVC) is fed into the hot mixer hopper 3, liquid components (thermal stabilizer, lubricants, etc.) are weighed on a scale for liquid components 1 and fed into the hot mixer hopper 3, bulk components processability, filler, etc.) are fed into the hopper 2, equipped with scales, from where the bulk components enter the hot mixer 3, operating at a low speed of 740 rpm. After loading all the components, the stirrer rotation speed is switched to a high rotational speed of 1500 rpm, intensive mixing is carried out for about 8.5 minutes. When this occurs, the mixture is heated to 100-125°C. It is established that the time is 8.5 minutes. is sufficient to obtain a homogeneous high-quality mixture and heating to the indicated temperatures. Temperature control is carried out by thermocouples, which transmit information about the temperature to the control system 6, 7. After unloading the resulting mixture from the hot mixer 3, the mixture enters one of the cold mixers 4 with a constantly running mixer at a speed of 740 rpm. Then pigments and/or dyes are loaded into this cold mixer 4 (depending on the specification for the decorative film) and the mixture with pigments is mixed at a constant stirrer speed of 740 rpm and at the same time cools to a temperature below 60°C. Mixing takes place for up to 8 minutes. It has been established that this speed and time are sufficient for high-quality mixing of the mixture with the pigment and/or dye. The cooling of the mixture in the cold mixer 4 to a temperature below 60°C occurs due to the supply of water with a temperature of 24-27°C into the jacket of the cold mixer. After completion of the stage of mixing with the dye, the resulting colored composition is unloaded into an intermediate container 5, from which the composition enters the stage of extrusion and calendering. Extrusion is carried out by forcing a viscous melt of material or a thick paste through a forming hole. During calendering, the softened polymeric material is passed through a gap between rolls located in a horizontal plane. In this case, an endless tape is formed, the thickness and width of which can be adjusted.

As dyes and pigments, for example, titanium dioxide can be used - for dyeing white. To obtain other colors, a wide range of pigment and dye concentrates are used in liquid or powder form.

If it is necessary to introduce several dyes and pigments, both cold mixers can be used, for example, mixing with the dye is performed in one mixer, and the pigment is mixed in the other. In the event of a change to a different type of film, one cold mixer is stopped and serviced to ensure consistent coloring to the desired color.

As an impact modifier, an acrylic impact modifier, chlorinated polyethylene, methyl methacrylate-butadiene-styrene copolymer, for example, in an amount of 10 wt. % of the molding mass. The molding composition according to the invention contains a processability modifier, for example, a methyl methacrylate-acrylic ether-styrene copolymer, in an amount of from 1 to 2 wt. %, based on the molding mass, in particular 1 wt. %.

In addition, additional components are introduced into the composition. As a heat stabilizer, for example, an organotin sulfur-containing stabilizer such as dioctyltin-bis(thioglycolic acid)-2-ethyl-1-hexyl ether and monooctyltin-tris-(thioglycolic acid)-2-ethyl-1-hexyl ether is provided.

Mixtures of complex and glycerol esters, as well as saturated, unbranched aliphatic monocarboxylic acids, such as palmitic and stearic acid, are used as softeners. Kaolin or chalk is usually added as a tracking agent.

Antimony trioxide can also be used as a flame retardant, and a quaternary ammonium salt is added as a preferred antistatic agent.

The molding mass is subjected to extrusion and calendering. The powdered composition from the intermediate container 5 after the cold mixer 4 enters the loading zone of the extruder, where the mass is homogenized and melted, the viscous melt is forced through the forming hole, and then in the form of a bundle enters the gap between the first and second calender rolls located in the horizontal plane. In this case, an endless tape is formed, the thickness and width of which can be adjusted.

Further, in an internal and/or autonomous technological step, for example, a stretching process in the longitudinal and/or transverse direction can be carried out with a stretching ratio of 1.3 to 7. In this case, the film becomes thinner and acquires the ability to shrink (strong change in dimensions in the direction of stretching ).

The characteristics of the films obtained by the presented and known methods were measured, while the following indicators were evaluated:

1. Nominal film thickness in accordance with GOST 24944. Samples of at least 5 pcs. measured with a micrometer type MK-25, GOST 6507. Samples were used in the form of a strip 35 ± 5 mm long.

2. Tensile strength and ultimate elongation in longitudinal direction, following GOST 24944, clause 4.8. A tensile and universal testing machine with an electric drive, GOST 28840 was used. The limit of the permissible value of the load measurement error in the forward stroke should not exceed ± 1% of the measured load. The speed of movement of the grippers of the testing machine in the range of 90-110 mm/min should be ensured. Samples - at least 5 strips, (150 × 15) ± 1.0 mm, cut in the longitudinal direction.

3. Peel resistance. Explosive and universal testing machine with electric drive, GOST 28840. The limit of the permissible error in measuring the load in the forward stroke should not exceed ± 1% of the measured load. The speed of movement of the grippers of the testing machine in the range of 90-110 mm/min should be ensured. Drying cabinet providing temperature control at a temperature of 70±2°C. Sample in the form of a flat-truncated cone with a top 20 mm, length 250 mm, base 50 mm, at least 3 pcs.

4. Light resistance. The tests were carried out using the Suntest CPS artificial aging chamber.

5. Resistance to chemical attack. Equipment was used according to GOST ISO 4211-2012 or GOST 33095-2014.

6. Scratch resistance, measured using an Erichsen instrument, a digital microscope 1000x, a sample - a square of a film with a side of 100 mm, at least 3 pieces.

7. Heat resistance was tested in drying cabinets for a square of film with a side of 200 mm, at least 3 pieces.

8. Abrasion. Taber rotary abrasimeter, digital microscope 1000x, sample - a circle with a diameter of 106 ± 1 mm, at least 3 samples were used.

9. Gloss deviation was measured with a 20-60-85° gloss meter.

10. Color fastness using an X-Rite Ci4200/X-Rite Ci UV benchtop spectrophotometer (lab color measurement).

11. Change in linear dimensions under temperature exposure - a GOST 166 caliper was used, a metal measuring ruler GOST 427, a drying cabinet that provides temperature control at a temperature of 70 ± 2 ° C, a dial indicator with a division value of 0.01 mm GOST 577.

12. Tensile strength and ultimate elongation at elevated temperature. Explosive and universal testing machine with electric drive, GOST 28840. The limit of the permissible error in measuring the load in the forward stroke should not exceed ± 1% of the measured load. The speed of movement of the grippers of the testing machine in the range of 90-110 mm/min should be ensured. Caliper GOST 166. Metal measuring ruler GOST 427. Heat chamber.

For flooring films, the following was studied:

1. Abrasion. We used a caliper GOST 166, a metal measuring ruler GOST 427, a drum-type testing machine, the requirements of clause 6.1.3. GOST 1 1529, general purpose laboratory scales 2 class. accuracy, weighing limit up to 200 g, GOST 53228, entrenching knife.

2. Changing the linear dimensions of floor coverings under temperature exposure using a caliper GOST 166, a metal measuring ruler GOST 427, a drying cabinet that provides temperature control at a temperature of 70 ± 2 ° C, a dial indicator with a division value of 0.01 mm GOST 577.

3. Water absorption - general purpose laboratory scales 2-4 cells. accuracy, weighing limit up to 500 g, GOST 53228, caliper GOST 166, metal measuring ruler GOST 427, watches.

4. Weight 1 m ² - general purpose laboratory scales 2-4 cells. accuracy, weighing limit up to 500 g, GOST 53228, caliper GOST 166, metal measuring ruler GOST 427.

5. The strength of the interlayer bond - discontinuous and universal testing machine with an electromechanical drive, GOST 28840. The limit of the permissible value of the error in measuring the load in a straight stroke should not exceed ± 1% of the measured load. The speed of movement of the grippers of the testing machine in the range of 90-110 mm/min should be ensured. We used samples in the form of a square with a side of 100-150 mm. For the last test, a sample in the form of an arrowhead 180 × 70 mm was used.

Comparative tests have shown the advantages of the film obtained by the presented method. Strength characteristics (tensile strength, peeling resistance, scratch resistance) are 1.5-2 times higher for the film obtained by the claimed method.

The color characteristics (lightfastness, gloss deviations) are also superior to the prior art method.

Comparative data of methods for producing films of well-known manufacturers and films according to the invention are shown in table 1.

Comparative data confirm the high efficiency and productivity of the method, as well as obtaining higher strength and color characteristics of the film according to the present invention.

The presented method for obtaining a decorative film allows:

• reduce production time,

• get a high quality film,

• improve film strength,

• ensure a continuous transition to the production of films of new brands and colors,

• obtain a film with stable and reproducible color characteristics.

Claims (8)

1. A method for producing a polyvinyl chloride decorative film, including the stage of mixing suspension polyvinyl chloride, a stabilizer, an impact strength modifier and a processability modifier, a stage of mixing with pigments and / or dyes, a stage of extrusion processing of the composition and calendering the film, characterized in that one hot film is used at the mixing stages and two cold mixers, suspension polyvinyl chloride, a stabilizer, an impact strength modifier and a processability modifier are fed from the weighing equipment to the hot mixer at a stirrer speed of 740 rpm, then intensive mixing is carried out at a speed of 1500 rpm until the temperature of the composition reaches 100-125 °C, the hot composition is unloaded into one of the cold mixers and pigments and/or dyes are introduced with a constantly running mixer at a speed of 740 rpm, water at a temperature of 24-27°C is supplied to the cold mixer jacket, the composition is cooled to a temperature temperatures below 60°C, and before the stage of extrusion processing and calendering, the resulting colored composition is unloaded into an intermediate container. 2. The method according to claim 1, characterized in that a hot mixer is used, which is a hopper with a self-cleaning filter, an agitator, a horizontally opening lid, two openings for loading and a thermocouple for temperature control, while the lid is equipped with a safety limit switch to stop the mixer motor when opening the lid and viewing window. 3. The method according to claim 1, characterized in that two cold mixers are used in the production line. 4. The method according to claim 1 or 3, characterized in that each cold mixer is a hopper with two chamber walls, equipped with a stirrer in the form of a mixing blade, a lid, a feed and outlet and a thermocouple for temperature control, while the lid is made hydraulically openable and equipped with a safety switch to stop the mixer when it is opened, and both cold mixers are mounted on load cells. 5. The method according to one of paragraphs. 3, 4, characterized in that the process is controlled automatically using a control system to which mixer motors, safety limit switches, temperature control thermocouples, weighing equipment and load cells are connected. 6. Method according to claim 1, characterized in that during operation of the first cold mixer the second cold mixer is stopped for maintenance. 7. The method according to p. 1, characterized in that the transition from one film formulation to another is carried out without stopping the line. 8. The method according to p. 1, characterized in that cold mixers are used alternately.

Images