JPS59217744A - Wood-filled composite resin composition - Google Patents

Abstract

PURPOSE:The titled composition that is obtained by adding a modified polypropylene and an olefinic elastomer to polypropylene as a resin component, combining leaflets of inorganic filler with wood fluor as a filler and extruding them into an integrated plate, thus showning high impact strength, when it is formed into thinned products. CONSTITUTION:(A) A polypropylene, as a resin, is mixed with (B) a modified polypropylene, preferably maleic acid-modified polypropylene, and (C) an olefinic elastomer, preferably ethylene-propylene copolymer rubber, while (D) a wood filler, as a filler, is combined with (E) leaflets of inorganic filler, preferably flakes of talc or mica. Then, they are combined, preferably at a ratio of 45-40 A:3-5B:5-10C:20-40D:10-30E. USE:The resultant composition is suitable for use as a core material in car interiors.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a wood powder-containing composite resin composition suitable for board core materials of automobile interior materials, and particularly to one having improved impact resistance.

(Background of the Invention) As a type of core material used in automobile interior materials, a synthetic resin alone or a composite resin composition in which a filler is blended with this resin alone is used.

The latter is cheaper than the former and has improved overall physical properties such as improved tensile strength, bending strength, and heat distortion temperature, so it is used more often than resin alone.

As the resin, polypropylene (hereinafter referred to as PP), which is industrially the cheapest and most easily available, is used, and as the filler, wood flour obtained by pulverizing wood chips such as hardboard is used.

In such PP composite resins, the most economical method is to increase the blending ratio of filler and reduce the amount of resin.Currently, the standard is 50% PP (by weight, the same hereinafter): 50% wood flour. This mixture is melted and integrally extruded into a plate shape using a T-die or the like, and then subjected to secondary processing.

Currently, the thickness of board materials made from composite resin compositions containing this powder is 2 mm, and in order to further lightly oxidize such board materials, the thickness must be increased from the conventional 2 mm. , 1.5111111.1°0in+ It is necessary to make the thickness thinner.

However, when the wall thickness is reduced in this way, the impact strength is extremely reduced, and the mechanical strength is also significantly reduced.
Countermeasures are needed.

For example, in order to prevent a decrease in impact strength, the PP:
It is conceivable to increase the amount of the resin component from the wood flour blending ratio of 50:50, or to add a rubber component as a third component. However, in the case of PP, impact resistance as a single resin is originally low, and even if the resin content is increased, the impact resistance strength does not increase significantly.

On the other hand, when a rubber component is added, the mechanical strength decreases significantly, resulting in a board core material with a low total balance.

Furthermore, regarding the improvement of mechanical strength, as a filler,
Adding non-+111 filler in addition to wood flour, PP
It has been considered to replace part of the PP with modified PP.
In this case as well, contrary to the above, the impact strength decreases,
Moreover, this results in an increase in specific gravity, which is contrary to the purpose of weight reduction.

(Objective of the Invention) The object of the present invention is to make various required physical properties in the case of thinning almost comparable to those of conventional thickness, and at the same time, to improve the impact resistance in particular.

In order to achieve the above object, the present invention provides a wood flour-containing composite resin composition which is basically formed by mixing polypropylene as a resin component and wood flour as a filler and integrally extruding the mixture into a plate shape. In addition to partially blending modified polypropylene and olefin elastomer,
It is characterized in that part of the filler contains an inorganic filler whose particles are in the form of a plate.

In other words, in the present invention, instead of simply improving physical properties by simply adding a third component as in the past, these improvements and decreases are balanced in a well-balanced manner, resulting in a total improvement in impact resistance. It is designed to have almost no effect on other physical properties.

Of each material constituting the composite resin composition, the resin component is 50%, the filler is 50%, and the total is 100%, but the main component in the resin component is the above-mentioned PP,
By blending appropriate amounts of these modified polypropylene and olefin elastomer, the blend is made to be 50% of the total amount.

The filler also has wood flour as its main component, and a portion of it is replaced with an inorganic filler whose particles are in the form of plates.

Among the resin components, the modified polypropylene is a composition of polypropylene and one selected from polymerizable organic acids and their esters, such as maleic anhydride, acrylic acid, methacrylic acid, or their esters. ,
Or it is a partial copolymer with a copolymer, and the above-mentioned polymerizable material is a partial copolymer. ! The acid used is 1 to 10 mol, preferably 5 mol, partially copolymerized with respect to polypropylene, which is the above-mentioned base polymer.

More specifically, maleic acid-modified polypropylene.

Examples include acrylic acid-modified polypropylene and methacrylic acid-modified 5-polypropylene, and esters can also be used in the same manner as above.

This modified polypropylene has the function of imparting resilience between the polypropylene which is the main resin component and the wood flour and inorganic filler which constitute the filler.

In this sense, if it is less than 3% of the total amount, it will be less effective as a deterrent agent, and if it exceeds 5%, it will be uneconomical and the overall performance will be greatly reduced. The reason for this decrease in performance is originally that the tensile strength, bending strength, modulus, etc. of the modified polypropylene used in the present invention are inferior to homogeneous polypropylene. That is, if the amount exceeds a certain level, the performance of the modified polypropylene itself will dominate the board performance rather than the Najimase effect. Therefore, the range is 3% to 5%.

Examples of the olefin elastomer include J: ethylene-polypropylene copolymer rubber (hereinafter referred to as EP rubber), EVA, etc.
In the case of VA, it is desirable to use EP rubber because it has a relatively low softening point and poor heat resistance rigidity.

Also, the ratio of the EP rubber to PP is EP5
:PI)45 to EP10:PP4-0 is desirable.

That is, if the blending ratio of the EP rubber exceeds the above-mentioned value, the mechanical strength will drop significantly, and if it is below that range, no effect on impact resistance will be seen, so it is set within the above-mentioned range.

More specifically, the inorganic filler is one such as talc or mica whose crystalline form is scaly, and these inorganic fillers include:
Added to improve mechanical strength.

The ratio of wood flour to the inorganic filler is preferably in the range of 40 wood flour: 10 wood flour to 20 wood flour: 30 wood flour, and if it exceeds this range, the impact resistance will drop significantly and the specific gravity will increase significantly. , or less, no improvement in mechanical strength can be expected.

Overall, PP: 35-40. Modified PP: 3-5
．． EP: 5-10. Wood flour: 20-40. Inorganic filler: 10 to 30 is a preferable range of the component composition ratio of this invention.

The above composition is uniformly diffused and mixed in a Henschel mixer, then melted in an extruder and extruded into a plate shape from a T-die.

Furthermore, when used as a core material for automobile interior materials, etc., it is then subjected to secondary processing such as cold or hot press molding.

The wood powder-containing composite resin constructed in this way is ideal for parts that require high rigidity, and when used as a core material in automobile interior materials, it has significantly improved impact resistance. In turn, this will make it possible to use thinner materials to achieve the same performance, greatly contributing to weight reduction.

In addition, other mechanical strengths, such as bending properties, bending rigidity, tensile strength, elongation, etc., which are disadvantages of the size that provides this high impact resistance, are not significantly different from the previous ones, and the current thickness is It has been confirmed that there is only a decrease in their mechanical properties when thinned from 211111.

(Description of Examples) Table 1 PP 40 Maleic acid-modified PP 3 EP 7 Wood flour 40 Talc 10'' (weight) The above compositions were thoroughly mixed and dispersed in a Henschel mixer, and then this composition was extruded into an extruder. 2 parts thick
+, 1, 5nv, 1, 0+nm plate-shaped extrusion molded bodies were obtained.

The results of comparing the impact resistance of these extruded bodies are shown in the table below.

In addition, in the comparative examples listed for comparison, ■ is the one in which the ratio of PP alone: wood flour is 50:50, and ■ is the one in the above ■100.
%, 5 parts and 10 parts of olefin-based Ella 9-store are added to the outside.
0%, 30% added to 20% wood flour, ■
is PP45: modified PP5. This shows the characteristics of a product containing only real flour.

10- As is clear from Table 2 above, with the composition according to the present invention, an extreme improvement in performance was observed, especially in the impact of falling balls. The thermal performance was also extremely high compared to the conventional products (1) to (3), and great effects such as excellent cold resistance were obtained.

patent applicant Kasai Kogyo Co., Ltd.

Claims (1)

[Claims] (1) In a composite resin composition containing wood flour, which is basically formed by mixing polypropylene as a resin component and wood flour as a filler and integrally extruding the mixture into a plate shape, a part of the resin component includes modified polypropylene and olefin-based A composite resin composition containing wood powder, which contains an elastomer and a part of the filler contains an inorganic filler whose particles are in the form of a plate.