CZ304791A3 - process of laminating composite mixtures wood flour - polyvinyl chloride - 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

BACKGROUND OF THE INVENTION Process for laminating pellets with rye beads polyviiyl wood | S ^ fipi_ $ oo

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The invention relates to a method for the continuous lamination of wood-PVC composite boards extruded by extrusion machines. The laminates produced by this process are characterized by improved appearance and strength para-parameters, reduced flammability and minimum water absorption.

Background Art

A number of industrial processes for the production of laminated thatched products using the waste paper, textile or wood processing industries are known. This includes the production of particleboard, fibreboard, sheath plates, in which the waste, fine-grained or fibrous material of plant origin is bonded with thermosetting (urea-formaldehyde, phenol-formaldehyde, melamine) resins in a new mass, usually flat in shape, to the next step decorative and / or insulating layer, usually paper-impregnated, with thermosetting resins again. The laminates produced in this way, used mainly in the furniture and housing industry, are characterized by a wide variability of external appearance, but are flammable, water-absorbent, of low strength and therefore unsuitable for use in humid environments and exteriors. In many cases they release formaldehyde. restrictions on their use in the furniture and housing industries,

Thin foils with or without an adhesive layer are also used for the lamination of wood veneers or boards. In technological processes of this type, the lamination foil is bonded to the wood substrate by hot pressing (e.g. German patent 3,516,645 or Japanese patents 58 185 247 and 59 51 910), thatched and veneer sheets prepared according to these laminating steps. Thus, they have increased water resistance and improved aesthetic appearance. However, because of the high content of eventual wood, they are flammable, especially when the laminating film is PVC but polyolefin.

Polypropylene, polyethylene and PVC thermoplastics have also proven themselves in the preparation of composite processing compositions containing pulp waste materials of proper origin and wound and by re-processing by 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 fire flour is extremely perspective in terms of suppression. Mechanical and processing properties of coaposites PVC-wood meal is widely variable not only because of the varying ratio of the above mentioned basic components, but also because of the wide choice of quality and quantity of processing additives dosed into the processing mixtures.

The patent literature describes a large number of compositions with a wide variety of claimed benefits of processing and use. Japanese Patent 57 ISO 035 discloses that for a mixture of 15 parts by weight of wood flour or rice drawer in 100% by weight. PVC parts have found improved machinability of products than PVC-free filler products, whilst maintaining good mixability. Further specification is given in Japanese patent 59 53 546, according to which, after previous granulation, a mixture of 100 wt. PVC parts of polymerization stage 800 with 60 parts by weight of wood dust and with an organotin stabilizer system in the presence of epoxidized soybean oil and stearic acid on a 3 mm thick wood-faced plate with a smooth surface. Further 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, a flexural modulus of elasticity E ^ - 8.6 GPa, and a Vicat flicker point of 113 ° C.

Other focus my processing mixture according to ^? Japanese Pat. 61 233 061 and no. 61 236 858, consisting of 100 wt.

PVC parts, 20 wt. parts by weight of dioctyl phthalate, 3 wt. parts by weight of 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 KAKEGAFUCHI through Japanese patents δ. 62 64 837, 62 64 838, 62 64 839, 62 64 840 protects rolling-rollable, high-impact, high-impact, wood-look and hand-mix compounds The essence of these mixtures is a combination of PVC, wood soap and wood bag vaccinated with vinylchloride The use of Ca-Zn, and Bs. 2n stabilizer and other stabilizing ingredients. Bringing these inventions into consideration, the cellulosic chain inoculated with vinyl chloride or methyl methacrylate improves the compatibility of wood powder and PVC, and another degree of technical improvement. Extracts from camping materials are achieved by laminating them. German patent no.

235,625 discloses a process wherein a 2.5 mm thick board consisting of 38% by weight wood isotactic polypropylene is laminated by pressing a 0.5 mm thick softened PVC film with a 35% DOP content, using as an adhesive layer Polyurethane Resin Powder · The laminate resulting from this procedure is not laminated even at SC ° C and is recommended for automotive interiors.

The lamination of isctactic polypropylene filled with woodfloor in a ratio of 62 parts by weight is also described in German Patent No. 3,136,257. According to this patent, a 400 µm adhesive layer (PVC - tetrahydrofuran - LGP) is deposited on a PVC foil and µm in an amount of 125 g / mS. The thus treated film is then sintered to a carrier layer of filled polypropylene by compression at 200 ° C.

Laminates made of composite wood poppy polypropylene, however, despite the thin surface layer of PVC remain highly flammable and their production is laborious. In addition, processing of isctactic polypropylene requires temperatures above 200 ° C, but at these temperatures, wood dust already decomposes considerably, resulting in a black-brown coloration of the composite product produced.

SUMMARY OF THE INVENTION

Method of laminating wood flour-FVC composite extrudates consisting of 40 to 80 wt. parts by weight of the suspension and / or emulsion polyvinyl chloride having a polymerization stage of 800 to 1000, 20 to 60 wt. 2 parts by weight of wood flour prepared with urea-formaldehyde or phenol-formaldehyde resin; parts of the processing ingredients is carried out in such a way that the extruding protruding from the die of the extruder with a heat of 16? to 185 [deg.] C. is continuously laminated by not rolling 0.2 to 0.6 mm thick film of composition 90 and 97 wt. parts of a suspension of pelyvinyl chloride having a polymerization degree of 600 to 1000, 0.01 to 10 wt. parts of a plasticizer of polyvinyl chloride to masses, tin (II) and / or calcium (II) or lead (PVC) stabilizers, and also the flexural strength of the breast

0.5 to 1.0 wt. 0.02 to 5 wt. parts of pigments and fillers connected to a three-cylinder device with a temperature of 100 * 120 ° 0 with a cylindrical night charge of 400, ·. ·· ο *

Woodpecker-PVC laminates of the invention laminated in accordance with the present invention over traditional particleboard products exhibit variable appearance properties, reduced burriness, minimum water absorption, increased bending nedulo® elasticity, good impact strength

The wood-PVC composite compositions of the above-mentioned laminate extruders are prepared in two-stage high-shelf crisps (e.g., KBNSCHSL, PAPSNMSISR, TSUSIOKA, etc.) equipped with venting of the volatile fractions to provide autogenous heat generation in high-speed heat-recovery. Such mixing devices will provide a homogeneous, free-flowing, agglomerate of the composite mixture (wood flour - PVC - grease

- stabilizers - fillers - pigments), characterized by reduced moisture content, formaldehyde and other volatile substances and low susceptibility of wood particles to be separated from PVC grains during in-house transport.

For extrusion of wood flour-PVC composites suitable for lamination, it is advantageous to use double-screw extruders with conical as well as wavy sintering plates intended for sintering hard PVC mixtures, equipped with a decompression age zone to remove residual volatile constituents (humidity ε). in composite processing mixture ·

The extrusion temperature mode is selected according to the composition of the processing mixture, the type of extruder and extrusion die in the range of 145-185 ° C. The optimum linear velocity of the melt flow at the exit of the die is influenced by the articulation of the profile and the plasticizing efficiency of the extruder used, typically in the range of C, 7 to 1.2 m / min.

The actual lamination process according to the invention immediately follows the process of extrusion of the composite mixture, utilizing the melt heat exiting the extruder. In contrast to the conventional lamination processes used by pressing preformed plates in large-scale presses, large-scale presses are used. energy savings and reduces production effort.

For the lamination of composite thatched products, a three-cylinder machine with a cylinder diameter of more than 400 mm is used whose temperature, peripheral speed and intermediate distance are precisely controllable. The Xminification process consists in testing, simultaneously with the melting melt of the composite mixture, 0.2 to 0.5 mm thick xasinizing foils from the upper and lower sides of the inlet of the composite melt. all three layers in one reinforced composite laminate Commercially available polyvinyl chloride films of hard, softened and modified (for example OVROPOL) stabilized with tinned, lead or even calcium-zinc stabilizers selected according to the intended use of the produced laminate are usable for lamination. The temperature of the DC laminating rollers is adjusted so as to achieve sufficient adhesion of the film to the surface of the composite thatch, but the film must not adhere to the surface of the laminating rollers due to high temperatures.

Closing the air bubbles between the laminating film and the composite thatch is prevented by appropriately adjusting the inlet angle between the plane of the film and the plane of the composite melt drawn into the rolling device, the formation of transverse and longitudinal bands is prevented by the non-latching braking mechanism. »Foil exceeding 3% of the original width.

- 6 The laminate produced according to this procedure at the correct setting of temperatures, peripheral speeds and inter-axis spacing of the rollers is characterized by dimensional tolerances of depth below + Ο7Ο5 mm and a great balance of mechanical properties over the entire flat laminate.

The laminate exiting the three-cylinder is evenly drawn, air-cooled and automatically cut to the required dimensions. The marginal particles as well as the waste generated by the start of 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 composite wood flour - PVC layer stabilized polyvinyl chloride is given in the example section of this document.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Preparation of composite mixture:

The hot components of the two-stage mixer equipped with the venting of exhaust gases are successively metered in the individual components of the composite mixture:

24.7 kg wood flour with grain size below 800 µm

84.0 kg of slurry PVC with polymerization degree of 880 2.6 kg of lead PVC stabilizer based on 3PbO, PbSO4 and lead stearate 0.6 kg pentaerythritol distearate 0.6 kg montan wax 0.8 kg calcium stearate 0.7 kg polyacrylate a flow modifier of 0.8 kg of titanium dioxide

2.2 kg of floated chalk

3.0 kg of dioctyl phthalate

Stirring was continued until the temperature of the mixture autogeneously rose 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 the mixture is cooled at low speed

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- direct water cooling to 40 ° C. The bulk composite mixture thus blended is ready for extrusion processing. Extrusion of composite mixture:

The composite composition prepared according to the above process is extruded by a twin-screw extruder with mutually turning conical worms equipped with a metering device, a vacuum zone, a housing temperature and worm core temperature controller. The mixture dispenser and the screw speed controller adjust the extrusion ratios so that, at the desired hourly displacement (220 to 270 kg / hour), a 30 to 00 torque load of the screws is achieved, ensuring perfect rotting of the processed mixture at the set temperatures:

181

0, t * 175, 177, • zones ’

0-, core i 70 7 pn. c .. 'g X O' - * - g

Flastifi - tunnel of composite compound with screws is injected into wide extrusion head © equipped with internal throttle gate, adjustable outlet slot and temperature control along the whole

200 mm nozzle width. With proper assembly of the temperature mode of the head: (inlet 183 ° C, left to right symmetrically 174, 174, 1S7, 155, 167, 174, 174 ° C), throttle gate and outlet slot depth achieve the same exit melt velocity of the composite. the entire nozzle width in thickness tolerances even 0.1 mm. The protruding large-area melt is free of cracks, vacancies and blisters.

Laminate composite thatch:

Hot, large-area melt of wood-PVC composite mixture emerging from the slot of the broadband extrusion die, horizontally enters a three-cylinder rolling machine with 400 mm diameter rolls, 403.7 mm axial roll distance, with temperatures of 110, 110, 112 ° C and adjustable peripheral speed cylinders and exhaust 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 of dioctyl phthalate

1.5 wt. parts of the carboxycin stabilizer

0.7 parts by weight of pentaerythritol distearate

4.5 mass, parts of chalk (CaCOg) mass, part of titanium white (TiO ₉ ) of 0.2 mm thickness from the top and bottom side of the incoming melt, «The laminating films wound in the rolls are stretched at an angle less than required than 30 ⁰ to the 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 mixture of wood flour - PVC and the outer decorative-insulating layers consist of rolled foils of modified PVC (eg DUROFOL). The produced 3.7 mm thick laminate is drawn off at a speed of 0.75 m / min, air cooled and automatically sawed to the required degree. The depth distribution of the laminate produced has a relative standard deviation of 0.015. The bending mechanical strengths Jf, Ef and a _n exhibited relative standard deviations of 0.042, 0.037 and 0.08, regardless of the breaking direction.

The laminate produced according to example no. 1 is therefore mechanically isotropic ·

The mechanical properties of the laminated and non-laminated composite thatch compared to traditional fibreboard are given in the attached table.

sample and ⁿ 2 kO / m fy MPa ^E f MPa Water absorption of% mass laminated 13.8 60.4 2780 0,044 laminated 11.2 54.4 2890 0,190 Particleboard 2.7 30.0 3080 32.8

and _R - bending impact strength ČSN 640 612 fy - ultimate bending strength ČSN 640 607

- flexural modulus of elasticity - ČSN 640 614% water absorption ČSN 490 144

Laminated composite boards of the aforementioned properties are advantageously used in the exhibition and trade fair equipment.

Example 2

Preparation of composite mixture:

The hot components of the two-stage mixer equipped with venting gas exhaust are dispensed into the two components of the composite mixture in operation according to the following procedure:

Part I

40.0 kg wood flour with grain size below 800 ^ / per 0.460 kg pentaerythritol distearate 0.490 kg montan wax 0.608 kg calcium stearate

0.951 kg polyacrylate PVC flow modifier 0.504 kg titanium dioxide 1.380 kg float chalk (CaCO ^)

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

II. section

4.08 kg of suspension PVC with a polymerization stage of 880

4.908 kg of dioctyl phthalate

2,000 kg of lead stabilizer based on 3 PbO.PbSO4 and lead stearate

Stir until the temperature of the mixture reaches 155 ° C. A thermometer sensor controlling the slide 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 bulk mixture thus blended is ready for processing into a laminatable thatched material.

Extrusion of composite mixture:

The composite composition prepared according to Example 2 is processed by the extruder described in Example 1 to laminate thatch of 8 mm depth under the following conditions:

Tube core temperature 145 ° C, zone temperatures 1 to 4: 170, 172, 173, 17 ° C, 175 ° C, tunnel temperature 176 ° G. Extrusion die width 1200 mm, aperture aperture 7 mra. Nozzle temperatures: 178 ° C inlet, right to 1'ava zone temperatures are symmetrically spaced: 169,

169, 162, 160, 162, 169, 169 ° C, At an extrusion rate of 300 kg / hour, a 70-80% torque tightening of the screw and a proper throttle setting, a balanced melt output speed of the composite melt is achieved along the entire die width. in dimensional tolerances of depth +0.1 mm. The protruding large-area melt is free of transverse cracks, vacancies and puffs. Laminate composite thatch:

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

96.65 pbw of S-PVC 1.3 pbw of carboxycin stabilizer 0.8 pbw of distearne pentaerythritol 0.65 pbw of montene wax

0.6 parts by weight of a polyacrylate flow modifier 1.0 parts by weight of titanium white (TiCl 2) drawn into a three-cylinder machine at the same roller temperatures as in Example no. 1. However, in this case the axial distance of the rollers is adjusted to 408 mm and the peripheral speed of the top roller together with the speed of the withdrawal twin roller 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 thatch produced by this process are:

<f _f = 41 MPa

Ξ. = 3400 MPa I o ^e n ⁼ kJ / mc Area distribution of the depth a little relative standard deviation

0,049.

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

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Claims (1)

PATENT CLAIMS Process for laminating extruded wood flour mixtures comprising from 40 to 80 parts by weight of a suspension and / or emulsion polyvinyl chloride having a polymerization stage of 600 to 1000, 20 to 60 parts by weight of a wood-based material with a paste-like or urea-formaldehyde 3-formaldehyde formaldehyde. parts by weight of processing additives, characterized in that the extrudate emerging from the die of the extruder at a temperature of 165 to 185 ° C is continuously laminated with an additional 0.2 to 0.8 mm thick film of 90 to 97 parts by weight of a polyvinyl chloride slurry having a polymerization degree of 600 up to 1000, 0.01 to 10 parts by weight of a plasticizer of polyvinyl chloride, 1 to 4 parts by weight of a tin and / or calcium zinc or lead stabilizer of polyvinyl chloride, 0.5 to 1.0 parts by weight of an internal lubricant of polyvinyl chloride, 0.02 to 5 parts by weight. pigments and fillers on an attached three-cylinder cylinder with a roller temperature at 100 to 120 ° C with a cylinder diameter above 400 mm.