SU1666306A1 - Method for wood plastic production of base on two components binder - Google Patents

Abstract

The invention relates to the production of wood plastics and can be used in various sectors of the national economy for the manufacture of engineering and construction products. The purpose of the invention is to increase the strength and water resistance of wood-based thermoplastics. To do this, determine the linear thermal expansion coefficient (CTE) of thermoplastics on a TERMOFLEX dilatometer at a heating rate of 10 ° C / min. In this case, the change in the length of the sample with increasing temperature is recorded. The value of CTE can be determined in stationary conditions according to GOST 15173 - 70. The wood particle filler is dried to a moisture content of 4 - 6%. It is then mixed in a mixer at room temperature with granules or a powder of one of the two components of the binder having a lower CTE value. The resulting mixture is loaded into an extruder and the mixing of the wood particles with the binder component is continued at 150–220 ° C for 3–5 minutes. The mixing product is crushed into granules with a size of less than 5 mm. The granules are mixed with the second binder component, first in a mixer and then in an extruder. At the same time, the mixing temperature is 15 - 35 ° C higher than the softening temperature of the most heat-resistant component of the binder. The finished extrudate is crushed into pellets, which are processed by pressing or casting into the product. 2 tab.

Description

The invention relates to the production of wood plastics and can be used in various sectors of the national economy for the manufacture of engineering and construction products.

The purpose of the invention is to increase the strength and water resistance of wood-based thermoplastics.

The invention is illustrated by the following examples.

The following thermoplastics are used as wood plastic components: low density polyethylene 15803-020 (LDPE), high density polyethylene 277 (HDPE). Polypropylene 21030 (PP), PVC-E 6750 F polyvinyl chloride (PVC), UPM-325 polystyrene (PS) ). polyethylene secondary (Pevtor).

The filler was sawdust hardwood, fraction 1.0 / 0.4 and a mixture of shavings and sawdust of various wood species, fraction 3/1.

The linear thermal expansion coefficient (CLTR) of thermoplastics is determined on a Termoflex dilatometer at a heating rate of 10 ° C / min. In this case, the change in the length of the sample with increasing temperature is recorded. The CTE value is determined by the formula

,, one . BUT

 Yag

where D | - increment of the length of the sample in a given temperature range; specified temperature range; 0 is the sample length at t0.

The maximum temperature must be lower than the heat distortion temperature (melting T or T of glass transition) by no less than 50 ° C. For crystalline polymers, the Ti range is limited to 50-100 ° C, and for amorphous polymers - 30-35 ° C. Accordingly, the temperature range D D T in the first case can be 30–80 ° C, and in the second - 10–15 ° C.

The CTE value can also be determined in stationary conditions. The difference in the CTE values of thermoplastics determined by these two methods is not significant.

Information about the value of LTFE for many polymers can be used to control technological parameters in the manufacture of wood plastic. The melt viscosity of a thermoplastic is correlated by its melt flow rate (MFR). In view of the availability of measurement, the MFR is used to estimate the melt viscosity of the binder components. The measurement is carried out on an IIRT-2 instrument at 190 ° C and a load of 2.16 kg.

To mix the filler and binder at a temperature above the softening temperature of the thermoplastics, a single-screw extruder from Reifeuhauser is used.

Wood plastic is made as follows. The filler is dried at 120-250 ° C to a moisture content of 4-6%, after which it is mixed in a mixer at room temperature with granules or powder of one of the binder components having a lower CTE value. The resulting mixture is loaded into an extruder and the mixing of wood particles with the binder component is continued at 150–220 ° C (15–35 ° C higher than the softening temperature of the thermoplastic). Within 3-5 minutes The mixing product is crushed into granules with a size of less than 5 mm. The granules are mixed with the remaining (second) component of the binder, first in the mixer and then in the extruder. At the same time, the mixing temperature does not exceed the softening temperature of the most heat-resistant component of the binder. Ready

The extruder is crushed into pellets that are processed by extrusion or injection molding into products, or standard samples for testing.

Pressing is carried out at 170-200 ° C and

pressure of 2-2.5 MPa, followed by cooling to 60-70 ° C under a pressure of 0.1 MPa. Injection samples are obtained at 160-190 ° C according to the conventional technology.

Various variants of the composition of the two-component binder and the technology of its combination with wood particles, as well as the strength and water resistance of the wood-plastic samples obtained herewith, are given in Table. 1 and 2. There, for comparison, the results of tests of wood-based plastics made according to the prototype method and control samples are given. Control samples, in contrast to the prototype method, were obtained according to a technology that involves the sequential hot mixing of each component of the binder with wood particles.

Analysis of the data obtained suggests that the use of the invention

allows to increase the strength and water resistance of wood plastics based on a two-component thermoplastic binder 1.2-1.4 times as compared with the known method,

The presented data show that the invention improves the properties of wood plastics in a fairly wide range of ratios between the components of the binder. In particular, the ratio

0 between the components of the binder is 1: 0, 3-3.

Claims (1)

Invention Formula 5 A method of manufacturing wood plastic on the basis of a two-component binder, including determining the characteristic parameter of the binder and mixing its components with the filler, about that and with the aim of increasing the strength and water resistance of the wood plastic, using thermoplastic materials As a characteristic parameter, the linear coefficient is determined. 5 thermal expansion of thermoplastics, and the mixing of the components of the binder with the filler begin with a thermoplastic having a lower value of the coefficient of linear thermal expansion. Invention 10 T Beyond Parameters It ruzhek 1.5 0.7 0 O , 1.1 The order of mixing components of wood with wood particles: 1st component 2nd component Mixing temperature 2nd component 12 13 Jj 36 25 14 ten eight 31 thirty thirty 40 Composition of Lreaoplastics, May. 15 30 45 45 - 15 30 30 30 30 30 40 40 thirty thirty 40 15 45 45 15 30 30 thirty thirty 40 40 15 45 40 30 30 about O) O) with about about 40 40 40 40 Technology options