SK278246B6 - Lamination method of extruded pieces of composite mixtures wood flour - pvc - Google Patents

Abstract

The invention concerns a method of lamination, in which extruded boards of thickness from 2,5 to 10 mm, profiles both hollow and full, from composite mixtures of 20 to 60 weight parts of a wood flour, of 80 to 40 weight parts of polyvinylchloride with a polymerization degree of from 600 to 1000, of 3 to 20 weight parts of current processing polyvinylchloride additives, are continually laminated by on-rolling of comercionally available polyvinylchloride foils. A field of an adventagenous application of such foils lays in an arranging technique of exhibition grounds, fairs, in a scene decoration, in a housing, furniture, shipbuilding and automobile industry.

Description

(57) Annotation:

The present invention relates to a lamination process in which extruded sheets having a thickness of 2.5 to 10 mm, hollow and solid profiles of composite mixtures of 20 to 60 wt. parts of wood meal, 80 to 40 wt. parts of PVC with a polymerization degree of 600 to 1000, 3 to 20 wt. parts of conventional PVC processing additives are continuously laminatable by rolling commercially available PVC films. The area of preferred application of such laminates is in the arranging technology of trade fairs, fairs, stage decoration, in the housing, furniture, shipbuilding and automotive industries.

SK 278246-6

Technical field

The invention relates to a process for the continuous lamination of wood flour-PVC composite boards extruded by extruders. Laminates produced by this process are characterized by improved appearance and strength parameters, reduced flammability and minimal water absorption.

BACKGROUND OF THE INVENTION

A number of industrial processes for the production of laminated board products using the waste treatment of the paper, textile or woodworking industry are known. This includes the manufacture of particle board, fibreboard, sheath plates, in which the waste, small-scale or fibrous material of vegetable origin is combined with thermosetting (urea-formaldehyde, phenol-formaldehyde, melamine) resins into a new mass, mostly flat in shape. In the next step of the manufacturing process, the sheets are laminated by hot pressing a thin decorative and / or insulating layer, mostly paper-impregnated again with thermosetting resins. The laminate thus produced, mainly used in the furniture and housing industry, is characterized by a wide variability in external appearance, but is flammable, water-absorbent, of low strength and therefore unsuitable for use in humid environments and exteriors. In many cases they release formaldehyde, which has recently led to limitations in their use in the furniture and housing industries.

Thin foils with or without an adhesive layer are also used to laminate wood veneers or boards. In technological processes of this type, the lamination film is joined to the wood facing by hot pressing (e.g., German patent 3,516,645 or Japanese patents 58,185,247 and 59,519,910). Boards and veneers treated according to these laminating processes over non-laminated have improved water resistance and improved aesthetic appearance. However, due to the high content of natural wood, they are flammable, especially in cases where the laminating film is not of PVC but of polyolefin.

Thermoplastics such as polypropylene, polyethylene and PVC have also proven themselves in the preparation of composite processing mixtures containing pulp waste materials of various origin and grain, which can be processed by pressing, rolling, spraying and extrusion into products representing natural wood. The water resistance of these materials is also higher than that of natural wood.

Among these thermoplastic pulp dust composites, PVC-wood flour is particularly promising in terms of suppressed flammability. The mechanical and processing properties of the PVC-wood meal composite mixtures are widely variable not only because of the variability of the ratio of the above-mentioned basic components, but also for the rich choice of quality and quantity of processing additives dosed into the processing mixtures.

A large number of compositions with a wide variety of claimed benefits of processing and use are described in the patent literature. Japanese Patent 57190 035 discloses that in a mixture of 15 parts by weight of wood meal or rice husks in 100% by weight of the composition of the invention. parts of PVC found improved machinability of products than those of

PVC free of fillers, while maintaining good processability of mixtures. For further specification, see Japanese Patent 59 53 546, according to which a mixture of 100 wt. die5 hunting of PVC with a polymerisation stage of 800 with 60 parts by weight of wood dust and an organotin stabilizer system in the presence of epoxidized soybean oil and stearic acid on a 3 mm thick wood-touch plate with a smooth surface. Another Japanese patent no. No. 84,152,387 discloses a composite PVC: ABS: wood meal in a 20:20:60 ratio, roll workable with good toughness, an elastic modulus of elasticity E _f = 8.6 GPa and a Vicat softening point of 113 ° C.

Another aspect is the processing composition of Japanese Patent Nos. 61 233 061 and 61 236 858, consisting of 100 wt. parts of PVC, 20 wt. parts by weight of dioctyl phthalate, 3 wt. parts by weight of a water-absorbing gel, 5.5 wt. 20 parts by weight of stabilizing additives;

parts of wood dust. This injection-processable mixture gives products useful for decorating automotive and home interiors with reduced gloss, soft touch and woody appearance.

Japanese company KANEGAFUCHI through Japanese patents no. 62 64 837, 62 64 838, 62 64 839, 62 64 840 protects rolling and pressable compounds with high impact resistance, woody appearance and feel. The essence of these compositions 30 is a combination of PVC, wood flour inoculated with vinyl chloride or methyl methacrylate, using Ca-Zn and Ba-Zn stabilizers and other stabilizing additives. The benefit of these inventions appears to be that cellulose chains grafted with vinyl chloride or methyl35 methacrylate improve the compatibility of wood powder and PVC.

A further degree of technical improvement of composite material products is achieved by laminating them. German patent no. No. 3,235,625 discloses a process wherein a 2.5 40 mm thick board consisting of isotactic polypropylene with 38% by weight of wood meal is laminated by pressing a 0.5 mm thick film of soft PVC with a 35% DOP content using a polyurethane sprayed adhesive layer. rubber. 45 The laminate resulting from this process is not delaminated even at 90 ° C and is recommended for automotive interiors.

The lamination of isotactic polypropylene filled with wood meal in a ratio of 62 wt. According to this patent, a 400 μπi layer of adhesive (PVC - tetrahydrofuran - DGP) is applied to the PVC foil and sprinkled with wood flour with a change of <400 pm in a quantity of 125 g / m ² . The film thus treated is then bonded to a carrier layer of filled polypropylene by compression at 200 ° C.

However, despite the thin coating of PVC, wood flour polypropylene composites remain highly flammable and laborious to manufacture. In addition, the treatment of isotactic polypropylene requires temperatures above 200 ° C, but at these temperatures the wood dust already decomposes considerably, resulting in a dark brown coloration of the composite product.

SUMMARY OF THE INVENTION

Method of laminating prints of composite mixtures

2786 Wood flour - PVC, consisting of 40 to 80 wt. parts by weight of suspension and / or emulsion polyvinyl chloride having a polymerization degree of 800 to 1000, 20 to 60 wt. % of wood meal prepared with urea-formaldehyde resin and from 3 to 20 wt. parts of the processing additives are carried out in such a way that the extrudate emerging from the extruder die at a temperature of 165 to 185 ° C is continuously laminated by rolling a 0.2 to 0.8 mm thick film of a composition of 90 to 97 wt. parts by weight of suspension polyvinyl chloride having a polymerization degree of 600 to 1000, 0.01 to 10 wt. parts by weight of a plasticizer of polyvinyl chloride, 1 to 4 wt. 0.5 parts by weight of parts of tin and / or calcium zinc or lead PVC stabilizer; 0.02 to 5 wt. parts of pigments and fillers on a connected three-cylinder device with a cylinder temperature of 100 to 120 ° C with a cylinder diameter of over 400 mm.

The extrudates wood flour composites - laminated PVC of the invention compared to conventional particleboard exhibit variability of appearance properties, low flammability, minimum water absorption, increased flexural modulus Ef good impact strength, and "the flexural strength of the _F.

Wood flour-PVC composite compositions of the above-mentioned composition for the production of laminable extrudates are prepared in two-stage high shear mixers (eg of the HENSCHEL, PAPENMEIER, TRUSIOMA etc.) equipped with venting of the volatile fractions ensuring autogenous heat development in high shear. the low-speed mixer cooling stage. Such a mixing device will provide a homogeneous, free-flowing agglomerate of the composite composition (wood flour - PVC - lubricants - stabilizers - fillers - pigments), characterized by reduced moisture, formaldehyde and other volatile matter content and low susceptibility to wood particles from PVC grains during in-house transport.

For the extrusion of PVC wood flour composites suitable for lamination, double-screw extruders with conical and cylindrical worms intended to process hard PVC blends, preferably equipped with a decompression vacuum zone for suctioning residual volatile constituents (moisture and formaldehydes) present in the composite processor can be advantageously used.

The extrusion temperature mode is selected according to the composition of the processing mixture, the type of extruder and extruder in the range of 145 to 185 ° C. The optimum linear velocity of the melt flow at the exit of the molding tool is influenced by the articulation of the profile and the plasticizing efficiency of the extruder used, typically in the range of 0.7 to 1.2 m / min.

The actual lamination process according to our invention immediately follows the process of extrusion of the composite mixture, utilizing the heat of the melt emerging from the die (die) of the extruder. Unlike conventional laminating processes used by pressing pre-prepared plates in large-size presses, the process introduced by us brings great energy savings and reduces manufacturing effort.

For lamination of composite board products, a three-cylinder machine with a cylinder diameter of more than 400 mm is used, whose temperature, peripheral speed and inter-axis distance are precisely controllable. The lamination process consists in that, together with the hot melt of the composite mixture, laminating foils 0.2 to 0.5 mm thick are fed into the triple roll from the top and bottom of the incoming composite melt wood flour - PVC, and the rolling device joins all three layers into one reinforced composite laminate. Commercially available polyvinyl chloride films of hard, plasticized and modified (e.g. DUROFOL) stabilized with tin, lead, or even calcium zinc stabilizers selected according to the intended use of the produced laminate are useful for lamination. The temperature of the laminating rolls is adjusted so as to achieve sufficient adhesion of the film to the surface of the composite plate, but the film must not adhere to the surface of the laminating rolls due to high temperatures.

Closure of the air bubbles between the laminating film and the composite plate is prevented by appropriately adjusting the inlet angle between the plane of the laminate and the composite melt plane drawn into the rolling device, the formation of transversal and longitudinal wrinkles can be prevented by the braking mechanism tensioning the laminating film. exceeding 3% of the original width.

The laminate produced according to this procedure at the correct setting of temperatures, peripheral speeds and inter-axial distances of the rollers is characterized by dimensional tolerances of thickness below + 0.05 mm and a great balance of mechanical properties over the entire surface of the produced laminate.

The laminate emerging from the three-cylinder is evenly drawn, air-cooled and automatically cut to the required dimensions. The marginal particles and wastes generated when starting the production line after grinding in a grain mill less than three millimeters are recycled to the cold part of the mixer.

More detailed information on the method of laminating extrudates from wood-PVC composite mixtures with a stabilized polyvinyl chloride layer is given in the example section of this specification.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Preparation of composite mixture:

The hot components of the two-stage mixer equipped with exhaust gas exhaust are gradually dosed with the individual components of the composite mixture on the fly:

24.7 kg wood flour with a change below 800 pm

84.0 kg of suspension PVC with a polymerization degree of 880

2.6 kg lead stabilizer PVC based on 3PbO. PbSO ₄ and lead stearate

0.6 kg of pentaerythritol distearate

0.6 kg montan wax

0.8 kg of calcium stearate

0.7 kg polyacrylate flow modifier

0.8 kg of titanium dioxide

2.2 kg of floated chalk

3.0 kg of dioctyl phthalate

Stirring is continued until the temperature of the mixture has autogenously increased to 155 ° C. The outflow of formaldehyde and water vapor released from the wood meal in the hot part of the mixer is sucked out of the working space by the ventilation device. By reaching the set mixing temperature, the hot mixer is fed into the cold part of the mixer, where at low temperatures the mixture is cooled by indirect water cooling to 40 ° C. The blended composite mixture thus prepared is ready for extrusion processing.

Extrusion of the composite mixture:

The composite composition prepared according to the above procedure is extruded by a twin-screw extruder and by means of a turning conical screw equipped with a metering device, a vacuum zone, a housing temperature regulator and a screw core. The mixture dispenser 10 and the screw speed controller adjust the dispensing ratios such that at the desired hourly displacement (230 to 270 kg / hour) a 60 to 80% torque load of the worms is achieved, ensuring perfect kneading of the processed mixture at set temperatures: 15 ° C 145 ° C t _zone 175, 177, 178, 180 ° C Tf 181 ° C. The plastic compound of the composite mixture is screwed into the wide extrusion head equipped with an internal throttle gate, adjustable outlet slot and temperature control along the entire 1200 mm nozzle width. When the temperature mode of the warhead is correctly set: (inlet 183 ° C, left to right 174, 174, 167, 165, 167, 174, 174 ° C), throttle and outlet gap thickness achieve the same melt velocity of the composite along the entire nozzle widths in thicknesses of 25 rants + 0.1 mm. The protruding large surface melt is free of cracks, vacancies and blisters.

Laminating of composite board:

Hot, large-area melt of composite compound 30 wood flour-PVC emerging from the wideband extrusion die slot into a three-cylinder rolling machine with 400 mm diameter rollers, 403.7 mm axial roll distance, 110, 110, 112 ° C and adjustable roller circumferential speed i towed equipment. Together with the hot 175 ° C hot melt of the composite mixture, laminating films of the following composition are fed into the triple roll:

90.8 wt. parts S-PVC wt. parts of dioctyl phthalate 40

1.5 wt. parts by weight of carboxycin stabilizer 0.7 wt. parts of pentaerythritol distearate

4.5 wt. parts of chalk (CaCO3) wt. a portion of 0.2 mm thick titanium bleach (TiO 2) from the top and bottom of the incoming melt. After the necessary braking and guidance, the laminating films rolled in rollers are drawn at an angle of less than 30 ° C into a three-cylinder which, under the influence of temperature and precisely adjusted pressure, joins all three layers into one laminate in which the core consists of a composite wood meal. - PVC and external decorative insulation layers consist of rolled foils of modified PVC (eg DITROFOL). The produced 3.7 mm thick laminate is drawn off at a speed of 0.75 m / min, air cooled, and automatically cut to the required dimensions. The thickness distribution of the laminate produced has a relative standard deviation of 0.015. The bending mechanical strengths 6f, Ef and a / 'showed relative standard deviations of 0.042, 0.037, and 0.08 regardless of the breaking direction. Thus, the laminate produced by Example 1 is mechanically isotropic.

The mechanical properties of the laminated and non-laminated composite board as compared to a traditional fibreboard are shown in the attached table.

sample KJ / m ¹ Sr MPa Er MPa Soak up water * / mass laminating 13, S 60.4 2780 0,044 Neleminovaiiá Π.2 54.4 2890 0,190 Drewtned » 2.7 30.0 3Μ0 32, i

a '- flexural impact strength ô _f - ultimate flexural strength E _r elastic modulus of elasticity% water absorption

CSN 640 612

CSN 640 607

CSN 640 614

ČSN 490144

Laminated composite boards of the aforementioned properties are preferably used in the fair and trade fair arrangement technique.

Example 2

The hot components of the two-stage mixer equipped with the exhaust gas venting are dosed on the fly with the components of the composite mixture in two parts, according to the following procedure:

Part I

40.0 kg wood flour with a change below 800 pm 0.460 kg pentaerythritol distearate 0.490 kg montan wax 0.608 kg calcium stearate

0.551 kg PVC polyacrylate flow modifier 0.504 kg titanium dioxide

I, 380 kg of floated chalk (CaCO ₃ )

The mixture was stirred until the temperature of the mixture rose to 135 ° C autogenously. The volatile fraction is ventilated outside the working area. At this temperature with continuous stirring, a second portion of the composite composition having the following composition is added:

II. section

40.08 kg of suspension PVC with a polymerization degree of 880

4.908 kg of dioctyl phthalate

2,000 kg of lead stabilizer based on 3 PbO.PbSO ₄ and lead stearate

Stir until the temperature of the mixture reaches 155 ° C. A thermometer sensor actuating the slider valve passes the swirling contents of the hot mixer to a cold mixer where it is cooled to 40 ° C by indirect water cooling while stirring the mixture. The blended bulk mixture is ready for processing into a laminatable sheet material.

Extrusion of composite mixture:

The composite composition prepared according to Example 2 is workable by the extruder described in Example I to laminate boards of 8 mm thickness under the following conditions: core temperature of 145 ° C, zone temperatures 1 to 4.: 170, 172, 173, 175 ° C, temperature tunnel 176 ° C. Extrusion nozzle width 1200 mm, aperture aperture 7 mm. Nozzle temperatures: 178 ° C inlet, right to left zone temperatures are symmetrically distributed: 169, 169, 162, 160, 162, 159, 169 ° C. With an extrusion weight rate of 300 kg / hour, a torque load of 70-80% of the screw and a proper throttle setting, a balanced composite melt output velocity is achieved along the entire die width within a thickness tolerance of +0.1 mm. The protruding large-area melt is free of crossbars4

2786 cracks, vacancies and blisters.

Laminating of composite board:

The melt of a composite blend of 1200 mm width and a thickness of 7.9 to 8.1 mm with a temperature of 170 ° C emerging from the die of the extruder is, together with laminating foils having the following composition:

96.65 parts by weight of S-PVC

1.3 parts by weight of carboxycin stabilizer 0.8 parts by weight of pentaerythritol distearate 0.65 parts by weight of montan wax

0.6 parts by weight of a polyacrylate flow modifier

1.0 parts by weight of titanium bleach (TiO ₂ ) drawn into a three-cylinder apparatus at the same roller temperatures as in Example 1. However, the axial spacing of the rollers in this case is adjusted to 408 mm and the peripheral speed of the top roller together with the speed of the twin-roll is set to 0.43 m / min. The board, drawn at a uniform speed without tension, is air-cooled and automatically cut to predetermined dimensions. The mechanical properties of the laminated board produced according to this process are: δ _f = 41 MPa

_Ef = 3400 MPa and = = 5.6 kJ / m

The areal thickness distribution had a relative standard deviation of 0.049.

Boards of such properties are advantageously used in the furniture and housing industry for the production of low-flammable parts with frequent contact with water.

Claims (1)

Process for laminating extruded wood flour-PVC composite compositions consisting of 40 to 80 wt. parts by weight of suspension and / or emulsion polyvinyl chloride having a polymerization degree of 600 to 1000, 20 to 60 wt. 3 parts by weight of wood flour prepared with urea-formaldehyde or phenol-formaldehyde resin; parts of processing additives, characterized in that the extrudate exiting the extruder die at a temperature of 165 to 185 ° C is continuously laminated by rolling a 0.2 to 0.8 mm thick film of 90 to 97 wt. parts by weight of suspension polyvinyl chloride having a polymerization degree of 600 to 1000, 0.01 to 10 wt. parts by weight of a plasticizer of polyvinyl chloride, 1 to 4 wt. 0.5 parts to 1.0 wt. 0.2 parts by weight of polyvinyl chloride internal lubricant; parts of pigments and fillers on a connected three-cylinder device with a cylinder temperature of 100 to 120 ° C with a cylinder diameter of over 400 mm.