CZ2022379A3 - The method of production of reoriented lightweight polyolefin sheets - Google Patents

Abstract

The production method consists in continuously extruding or unrolling a square or rectangular profile, or continuously extruding or unrolling a strip of longitudinally oriented and lightened polyolefin, which is transversely divided into blanks or sheets of longitudinally oriented lightened polyolefin are continuously fed. Blanks or plates are joined in the area by welding or gluing into a gradually created block. The block obtained in this way is subsequently cut transversely into sheets. After cutting the longitudinal edges to the final width, these plates can already represent finished plates with a reoriented structure, or they are still connected by welding or gluing in the transverse direction to an endless plate, which is then divided into plates of the final length, which then, after the longitudinal edges are cut to the final width they represent finished boards with a reoriented structure.

Description

Method of production of reoriented lightweight polyolefin sheets

Field of technology

The invention relates to a method of manufacturing reoriented lightweight polyolefin boards, especially semi-finished products (core boards) for the production of sandwich boards, laminated on both sides with a surface layer that has a reinforcing function and/or a protective function against physical and chemical external influences and/or a decorative function.

Current state of the art

Physically lightened, extruded polyolefin foam, lightened with butane, propane, freon or CO ₂ , in the form of a foil or in the form of a square profile or a rectangular profile, has a significantly higher compressive strength in the longitudinal direction (in the direction of extrusion) and a significantly higher compressive modulus than the strength in pressure and modulus in pressure in the direction of the width or thickness of the foil or profile.

This fact is used in multi-layer, especially sandwich lightweight boards, which in their structure contain lightweight core boards with the direction of extrusion perpendicular to the cover layers of the final multi-layer board.

An example of such a solution is, for example, the Chinese utility model CN 216300437 U, which relates to high-strength composite sheets made of polyethylene terephthalate (PET). These contain a PET foam core board cross-cut from a lightweight PET board. The upper front side of this core board is connected by the upper layer of hot melt adhesive to the upper layer of the non-woven fabric and the lightweight board attached to it, as well as the covering surface layer. The bottom surface of the core board is connected with the bottom layer of the non-woven fabric by the bottom layer of hot melt adhesive and the lightweight board attached to it. As a covering surface layer, a layer resistant to weather effects, resistant to ultraviolet radiation, etc. can be used. As a result, the entire composite board is also resistant to these effects. Aging resistance can be further customized according to requirements. The composite board is made of PET materials and is not susceptible to damage due to the fact that its composite structure has been created in a heat treatment mode.

Similar to other well-known published materials, however, in the above-mentioned Chinese utility model, the manufacturing method of the core board with the direction of extrusion perpendicular to the cover layers of the final multilayer board is not specified in any detail, and therefore not optimized from a technological point of view.

The essence of the invention

The method of producing reoriented lightweight polyolefin sheets according to the invention contributes to a large extent to the elimination of the above-mentioned deficiency. Its essence is that aa) a square or rectangular profile of longitudinally oriented and calibrated lightweight polyolefin with a thickness of 5 to 200 mm, a width of 100 to 400 mm and a bulk weight of 30 to 300 kg/m ³ is continuously extruded or unwound, and then transversely divides into blanks with a length of 400 to 4000 mm; or ab) sheets of longitudinally oriented lightweight polyolefin with a thickness of 5 to 1250 mm, a width of 100 to 2600 mm, a length of 400 to 4000 mm and a bulk weight of 30 to 300 kg/m ³ are continuously fed, prepared in advance by longitudinal connection of several elements with a composition clearly in direction of longitudinal orientation; or you

- 1 CZ 2022 - 379 A3 ac) continuously extrudes or unrolls a strip of longitudinally oriented and calibrated lightweight polyolefin with a thickness of 1 to 100 mm, a width of 100 to 2600 mm and a bulk weight of 30 to 300 kg/m ³ , and then transversely divides it into blanks of length 400 to 4000 mm;

b) the blanks or plates are then joined by welding with the possible use of residual heat after extrusion or gluing into a gradually created block with a thickness of 10 to 3000 mm, containing 2 to 500 layers of blanks of the original lightweight profile, strip or plate;

c) the block obtained in this way is subsequently cross-cut into plates with a thickness of 2 to 500 mm after any lateral alignment from the top and other sides, with the proviso that

d) after processing the contact edges, if the lateral alignment of the block has not been carried out, these sheets are joined by welding or gluing in the transverse direction to form an endless sheet, which is subsequently divided into sheets with a final length of 100 to 15,000 mm, which then, after trimming the longitudinal edges on the final width of 100 to 2600 mm is represented by finished boards with a reoriented structure.

The actual joining of blanks in the area is preferably carried out by welding with thermocontact (fusion) heating or welding with hot air heating or welding with infrared heating or gluing.

Cross cutting of the resulting block is preferably done with a resistance wire, band saw or high speed wire.

Cutting or milling is used to process the contact edges of the plates before joining. The joining of the processed plates is then preferably carried out by welding with thermocontact (fusion) heating or welding with hot air heating or welding with infrared heating or gluing.

Physically lightened, extruded polyolefin, e.g. polypropylene foam, lightened with butane, propane, freon or CO2, in the form of a foil or in the form of a square profile or a rectangular profile can be extruded during or immediately after extrusion.

With this orientation, under the influence of higher temperature and force, the lightened structure is elongated in one direction, and thus the cells are oriented into an elongated shape. Ensuring this oriented state is subsequently carried out by cooling the oriented foam immediately after the orientation.

A simplified interpretation of the orientation principle is shown in Fig. 1a to 1c. Fig. 1a shows the dimensional changes of the lightweight structure element in the direction of orientation, most often longitudinal (i.e. orientation in the direction of extrusion). Giant. 1b shows a longitudinal section of a model discrete cell of a lightweight structure before and after orientation. Foam oriented in this way has a significantly higher compressive strength in the direction of orientation and a significantly greater compressive modulus than compressive strength and compressive modulus than in the remaining directions (2 directions perpendicular to the direction of orientation). See the loading diagram of the model discrete cell after the orientation process shown in Fig. 1c, where the polypropylene foam oriented in this way has these mechanical parameters specified in Fig. 1c.

With such oriented foam, the compressive strength and compressive modulus can be significantly increased in the next step, by the additional process of foam reorientation according to the method according to the invention, when compressed in the direction of the thickness of the relevant lightened semi-finished product or product. The course of compressive strength of polypropylene foam in the direction of orientation during compression is shown graphically in Fig. 2, the course of the compressive modulus of polypropylene foam in the direction of orientation during compression is shown in Fig. 3.

This process of reorientation can be applied just after the previous process of orientation from still uncooled foam or additionally from cooled foam wound into a coil and cut. It is also possible to process foam produced in advance in the form of boards combined from several foam elements that have undergone an orientation process (typically, for example, boards prepared by welding several layers of foam

- 2 CZ 2022 - 379 A3 polypropylene strip on top of each other or plates prepared by welding several rectangular profiles of lightweight polyolefin next to each other).

Reoriented sheets of lightweight polyolefin with a width of 100 to 2600 mm, a length of 100 to 15,000 mm and a thickness of 2 to 500 mm can be prepared by the methods mentioned below. These boards can have a volume weight of 30 to 300 kg/m ³ .

Reoriented boards made of lightweight polyolefin (e.g. polypropylene) produced by the mentioned variants of the method according to the invention are primarily intended for the production of sandwich boards, laminated on both sides with a surface layer that has a reinforcing function and/or a protective function against physical and chemical external influences and/or decorative function.

Depending on the method of use, reoriented plates made of light polypropylene have a use temperature of up to -40 to 140 °C, a processing temperature of up to 155 °C. They are characterized by chemical resistance, high resistance to moisture, high non-absorption, good thermal insulation properties, high impact strength, high resistance to fatigue stress.

Reoriented boards made of lightweight polyolefin can be designed with increased resistance to UV radiation.

Reoriented boards made of lightweight polyolefin can also be designed with increased fire resistance.

By using reoriented boards made of lightweight polyolefin with suitable surface layers, significant weight savings can be achieved compared to conventional board types.

Furthermore, by using reoriented boards made of lightweight polyolefin with suitable surface layers and binders, the resulting sandwich boards can be significantly lighter in weight compared to commonly used wood and chipboard while maintaining similar strength and stiffness.

Clarification of drawings

The attached drawings serve to clarify the essence of the invention in more detail, where it represents:

Fig. 1a is a schematic representation of dimensional changes of an element of a lightweight structure in the direction of orientation;

Fig. 1b longitudinal section of the model discrete cell of the lightweight structure before and after orientation;

Fig. 1c is a schematic representation of the mechanical parameters during loading of a model discrete cell oriented lightweight polypropylene foam structure;

Fig. 2 is a graphical representation of the compressive strength of polypropylene foam in the direction of orientation during compression;

Fig. 3 is a graphical representation of the course of the compressive modulus of polypropylene foam in the direction of orientation during compression;

Fig. 4 is a technological diagram of the method according to the invention in a variant of reorientation by layering an endless lightweight polyolefin strip into a block with subsequent transverse cutting and joining into the required format;

- 3 CZ 2022 - 379 A3 Fig. 5 and a technological diagram of the method according to the invention in the variant of reorientation by layering sheets of lightweight polyolefin into a block with subsequent transverse cutting and joining into the required format;

Fig. 5b schematic representation of the plates used in the reorientation variant according to Fig. 5a;

Fig. 6 technological diagram of the method according to the invention in a variant of reorientation by cyclic layering of lightened polyolefin into a block using the residual heat after extrusion with subsequent transverse cutting and joining into the required format; and Fig. 7 is a technological diagram of the method according to the invention in a variant of reorientation with lateral connection of foamed polypropylene to the block using the residual heat after extrusion, with subsequent cross-cutting and joining into the required format.

Examples of implementation of the invention

Example 1

An exemplary embodiment of the method of manufacturing reoriented lightweight polyolefin boards according to the invention, in the variant of reorientation by layering an endless lightweight polyolefin strip into a block with subsequent transverse cutting and joining into the required format, is shown by the technological diagram in Fig. 4.

In this variant of the production of reoriented lightweight polyolefin, specifically polypropylene sheets, a strip 1b of longitudinally oriented and calibrated lightweight polyolefin with a thickness of 1 to 100 mm, a width of 100 to 2600 mm and a bulk weight of 30 to 300 kg/m ³ is continuously extruded or unwound, and subsequently transversely divides A into blanks 3 with a length of 400 to 4000 mm, which are then joined by welding with thermocontact (fusion) heating or welding with hot air heating or welding with infrared heating or gluing B in the area into a gradually created block 4 with a thickness of 10 to 3000 mm, containing 2 up to 500 layers of blanks 3 of the original lightweight strip 1.

The block 4 is then laterally aligned, transversely cut C into plates 5 with a thickness of 2 to 500 mm, and these plates 5 are then joined E by welding or gluing in the transverse direction to an endless plate 7 after processing D the contact edges 6. The transverse cutting C of the block 4 is performed with a resistance wire, band saw or high-speed wire, side alignment is performed with a resistance wire, band saw or high-speed wire or a milling cutter, processing D of the contact edges of 6 plates 5 before joining E is performed by cutting or milling.

The endless plate 7 is subsequently divided F into plates 8 with a final length of 100 to 15000 mm, which then, after trimming G of the longitudinal edges 9 to a final width of 100 to 2600 mm, represent finished plates 10 with a reoriented structure. The connection of the E plates 5 with the machined contact edges 6 is carried out by welding with thermocontact (fusion) heating or welding with hot air heating or welding with infrared heating or gluing.

Example 2

An exemplary embodiment of the method of manufacturing reoriented lightweight polyolefin boards according to the invention, in the variant of reorientation by layering boards from lightweight polyolefin into a block with subsequent cross-cutting and joining into the required format, is shown by the technological diagram in Fig. 5a.

In this version of the production of reoriented lightened polyolefin, specifically polypropylene sheets, sheets of 2 longitudinally oriented lightened sheets are continuously fed

- 4 CZ 2022 - 379 A3 polyolefin with a thickness of 5 to 1250 mm, a width of 100 to 2600 mm, a length of 400 to 4000 mm and a volume weight of 30 to 300 kg/m ³ . These plates 2 are prepared in advance by the longitudinal connection of several rectangular elements 2a (1 to 200 elements in the h direction; 1 to 200 elements in the w direction), with a cross-sectional area of each element of at least 1000 mm ² , with a composition clearly in the direction of longitudinal orientation (see Fig. 5b).

The plates 2 are then joined B in the area by welding with thermocontact (fusion) heating or welding with hot air heating or welding with infrared heating or gluing into a gradually created block 4 with a thickness of 10 to 3000 mm, containing 2 to 500 layers of plates 2.

The block 4 is then laterally aligned, transversely cut C into plates 5 with a thickness of 2 to 500 mm, and these plates 5 are then joined E by welding or gluing in the transverse direction to an endless plate 7 after processing D the contact edges 6. The transverse cutting C of the block 4 is performed with a resistance wire, band saw or high-speed wire, side alignment is performed with a resistance wire, band saw or high-speed wire or a milling cutter, processing D of the contact edges of 6 plates 5 before joining E is performed by cutting or milling.

The endless plate 7 is subsequently divided F into plates 8 with a final length of 100 to 15,000 mm, which then, after trimming G of the longitudinal edges 9 to a final width of 100 to 2600 mm, represent finished plates 10 with a reoriented structure. The connection of the E plates 5 with the machined contact edges 6 is carried out by welding with thermocontact (fusion) heating or welding with hot air heating or welding with infrared heating or gluing.

Example 3

An exemplary embodiment of the method of manufacturing reoriented lightened polyolefin boards according to the invention, in the variant of reorientation by cyclic layering of lightened polyolefin into a block using the residual heat after extrusion with subsequent transverse cutting and joining into the required format, is shown in the technological diagram in Fig. 6.

In this version of the production of reoriented lightened polyolefin, specifically polypropylene sheets, a strip 1b of lightened polyolefin with a thickness of 1 to 100 mm, a width of 100 to 1500 mm and a bulk weight of 30 to 300 kg/m ³ is continuously extruded, which is longitudinally oriented, calibrated K and subsequently transversely divides A into blanks 3 with a length of 400 to 4000 mm.

The blanks 3 are welded with the use of residual heat after extrusion to join B in the area into a gradually created block 4 with a thickness of 10 to 3000 mm, containing 2 to 500 layers of blanks 3 of the original lightened strip 1, while the extrusion lines are removed from the stock conveyor and cyclically layered layering applicator B1 to block 4. Hot air or infrared heating B2 is used to warm up the blanks before joining B.

The block 4 is cooled and then laterally aligned by cutting with a resistance wire, band saw or high-speed wire or milling with a milling cutter, cross-cut C with a resistance wire, band saw or high-speed wire into plates 5 with a thickness of 2 to 500 mm, and these plates 5 are then machined D contact edges 6 by cutting or milling connect E by welding with thermocontact (fusion) heating or welding with hot air heating or welding with infrared heating or gluing in the transverse direction to the endless sheet 7.

The endless plate 7 is subsequently divided F into plates 8 with a final length of 100 to 15000 mm, which then, after trimming G of the longitudinal edges 9 to a final width of 100 to 1500 mm, represent finished plates 10 with a reoriented structure.

- 5 CZ 2022 - 379 A3

Example 4

An exemplary embodiment of the method of manufacturing reoriented lightweight polyolefin boards according to the invention in the variant of reorientation with lateral connection of foamed polypropylene to the block using the residual heat after extrusion, with subsequent transverse cutting and connection to the required format is shown in the technological diagram in Fig. 7.

In this version of the production of reoriented lightweight polyolefin, specifically polypropylene sheets, a rectangular profile 1a of lightweight polyolefin with a thickness of 5 to 100 mm, a width of 50 to 1000 mm and a bulk weight of 30 to 300 kg/m ³ is continuously extruded, which is oriented longitudinally, calibrated K and subsequently divides A transversely into blanks 3 with a length of 400 to 4000 mm.

The blanks 3 are welded using the residual heat after extrusion to connect B in the surface into a gradually created block 4 with a thickness of 50 to 1000 mm, containing next to each other 2 to 500 layers of blanks 3 of the original lightweight profile 1, while the extrusion lines are removed from the stock conveyor, heated by hot air heating B2 or infrared heating, positioned and connected to a continuous block 4a when passing through the input connecting conveyor B3 and compression conveyor B4, which is then cut B6 into individual blocks 4 after cooling on the cooling conveyor B5.

Each of the blocks 4 prepared in this way is then laterally aligned by cutting with a resistance wire, band saw or high-speed wire or by milling with a milling cutter, cross-cut C with a resistance wire, band saw or high-speed wire into plates 5 with a thickness of 2 to 500 mm, and these plates 5 are then processing D contact edges 6 by cutting or milling connect E by welding with thermocontact (fusion) heating or welding with hot air heating or welding with infrared heating or gluing in the transverse direction to an endless sheet 7.

The endless sheet 7 is subsequently divided F into sheets with a final length of 100 to 15,000 mm, which then, after trimming G of the longitudinal edges 9 to a final width of 100 to 2600 mm, represent finished sheets 10 with a reoriented structure.

Example 5

An exemplary embodiment of the method of manufacturing reoriented lightened polyolefin boards according to the invention is a variant of reorientation by layering an endless lightened polyolefin strip into a block with subsequent cross-cutting and joining into the required format according to the technological diagram in Fig. 4.

In this version of the production of reoriented lightweight polyolefin, specifically polypropylene sheets, a strip 1b of longitudinally oriented and calibrated lightweight polyolefin with a thickness of 1 to 100 mm, a width of 100 to 2600 mm and a bulk weight of 30 to 300 kg/m ³ is continuously extruded or unwound, and subsequently divided transversely to blanks 3 with a length of 400 to 4000 mm, which are then joined by welding with thermocontact (fusion) heating or welding with hot air heating or welding with infrared heating or gluing B in the area into a gradually created block 4 with a thickness of 10 to 3000 mm, containing 2 to 500 layers of blanks 3 of the original lightweight strip 1.

Block 4 is then laterally aligned, C is cut crosswise into plates 5 with a thickness of 2 to 500 mm, and the contact edges D are processed on these plates. The transverse cutting of C block 4 is done by resistance wire, band saw or high-speed wire, side alignment is done by resistance wire, band saw or high-speed wire or milling machine, machining D of contact edges 6 of plates 5 is done by cutting or milling. The connection of the E plates 5 with the machined contact edges 6 is then no longer performed in this variant.

- 6 CZ 2022 - 379 A3

The resulting plates 8 with a final length of 10 to 3000 mm, which then, after trimming G of the longitudinal edges 9 to a final width of 100 to 2600 mm, represent finished plates 10 with a reoriented structure.

Industrial applicability

The method of production of reoriented lightweight polyolefin boards according to the invention serves mainly for the preparation of semi-finished products (core boards) for the production of sandwich boards. In them, the respective core board is laminated on both sides with a surface layer that has a reinforcing function and/or a protective function against physical and chemical external influences and/or a decorative function corresponding to its specific application.

Claims (6)

1. Method of production of reoriented lightweight polyolefin boards, especially semi-finished products for the production of sandwich boards laminated on both sides with a surface layer that has a reinforcing function and/or a protective function against physical and chemical influences and/or a decorative function, characterized by the fact that aa) continuously extrudes or unwinds a square or rectangular profile (1a) of longitudinally oriented and calibrated lightweight polyolefin with a thickness of 5 to 200 mm, a width of 100 to 400 mm and a bulk weight of 30 to 300 kg/m ³ and is subsequently divided transversely (A) into blanks ( 3) with a length of 400 to 4000 mm; or ab) sheets (2) of longitudinally oriented lightweight polyolefin 5 to 1250 mm thick, 100 to 2600 mm wide, 400 to 4000 mm long and 30 to 300 kg/m ³ are continuously fed, prepared in advance by longitudinal connection of several elements ( 2a) with the composition clearly in the direction of longitudinal orientation; or ac) a strip (1b) of longitudinally oriented and calibrated lightweight polyolefin with a thickness of 1 to 100 mm, a width of 100 to 2600 mm and a bulk weight of 30 to 300 kg/m ³ is continuously extruded or unwound, and then transversely divided (A) into blanks ( 3) with a length of 400 to 4000 mm; after which b) blanks (3) or plates (2) by welding (B) with possible use of residual heat after extrusion or gluing, join in the surface into a gradually created block (4) with a thickness of 10 to 3000 mm, containing 2 to 500 layers of blanks of the original lightweight profile , belt or plate; c) the block (4) obtained in this way is subsequently cross-cut (C) into plates (5) with a thickness of 2 to 500 mm, after possible lateral alignment from the top and other sides, with the fact that d) these sheets (5) are joined (E) by welding or gluing in the transverse direction to an endless sheet (7) after processing (D) the contact edges (6), if the lateral alignment of the block has not been carried out, and it is subsequently divided (F ) into plates (8) with a final length of 100 to 15,000 mm, which then, after trimming (G) of the longitudinal edges (9) to a final width of 100 to 2,600 mm, represent finished plates (10) with a reoriented structure. 2. The production method according to claim 1, characterized in that the blanks (3) are joined (B) in the surface by welding with thermocontact fusion heating or welding with hot air heating or welding with infrared heating or gluing. 3. The production method according to claim 1, characterized in that the lateral alignment of the resulting block (4) is performed with a resistance wire, a band saw or a high-speed wire or a cutter. 4. The production method according to claim 1, characterized in that the transverse cutting (C) of the resulting block (4) is performed with a resistance wire, a band saw or a high-speed wire. 5. The production method according to claim 1, characterized in that the processing (D) of the contact edges (6) of the plates (5) before joining (E) is performed by cutting or milling. 6. The production method according to claim 1, characterized in that the joining (E) of plates with machined contact edges (6) is performed by welding with thermocontact fusion heating or welding with hot air heating or welding with infrared heating or gluing.