JPS6019328B2 - Flexible crystalline polyolefin resin composite material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel crystalline polyolefin resin composite material containing a large amount of inorganic filler and having maneuverability.

Conventionally, so-called filled resin materials containing inorganic fillers have the effect of improving physical properties such as dimensional stabilizers and rigidity, providing easy incineration by reducing combustion heat, and reducing costs by increasing the amount. A considerable amount is used.

These existing filled resin materials have a high rigidity, high self-supporting strength, and excellent shape retention, as shown by the fact that their greatest applications are molded parts made by injection molding and trays made by sheet molding. It was a hard material. However, according to the present inventors, surprisingly, a composition in which a crystalline polyolefin resin is filled with 15 to 70% by volume inorganic particles that have been surface-treated with a titanate coupling agent is combined with the resin and inorganic particles. In order to achieve the present invention, the present invention has been achieved by discovering that a composite resin material obtained by treating the interfacial adhesion of It's arrived.

Therefore, the present invention provides a flexible, flexible composite resin material that has unique behavior that is completely different from conventionally known filled resins. The reason why the composite resin material of the present invention is a highly flexible and flexible material with low resistance to bending deformation even though it is based on a crystalline poIJ olefin resin is not necessarily clear, but it is explained as follows. It can be thought of as follows.

That is, since inorganic particles are used which have undergone a special surface treatment such as surface treatment with a titanate coupling agent, the fact that the inorganic particles are uniformly dispersed in the polymer matrix seems to have a great effect. Any method may be used as long as the inorganic particles are uniformly dispersed, but among them, those treated with the titanate coupling agent are so uniformly dispersed that almost no aggregation of the particles is observed. Furthermore, when an external stimulus is applied to a material made of a crystalline polyolefin resin filled with inorganic particles whose surface has been treated with a titanate coupling agent, the interfacial adhesion between the surface of the inorganic particles and the polymer matrix is destroyed. be. This shows that when the composite resin material of the present invention is viewed under a magnifying glass using an electron microscope or the like, voids are observed at the boundary between the particle surface and the polymer matrix, indicating that the adhesion between the two is destroyed. Therefore, the characteristics of the composite resin material of the present invention, which are extremely flexible against bending deformation, etc., are due to the fact that the polymer has good dispersibility and contains inorganic particles relatively uniformly, and the fact that voids are not formed at the particle interface. This appears to be the result of a synergistic effect between the two structures. Perhaps reflecting the above-mentioned structural features, the material of the present invention exhibits the following unique properties.

'1} Even at room temperature, it is extremely flexible to deformation such as bending, and is extremely flexible.

In addition, the added shape is maintained as is, and the restoring force is small.
■ There is little change in the thickness of the deformed part due to deformation, especially repeated deformation. For example, when bending deformation is applied, smooth sliding occurs at the interface between the particles and the polymer, and it is thought that the inorganic particles act as resistance against compression in the thickness direction, preventing the thickness from decreasing. Rigid Thick and soft sheet. Stretched films or stretched tapes have conventionally been used as comparatively sophisticated materials made of crystalline resins, but these are limited to extremely thin materials. On the other hand, in the present invention, a flexible sheet having a thickness of 10 sides or more is also possible. The composite resin material of the present invention is
As mentioned above, it is a unique material that exhibits flexible behavior similar to rubber, which is the complete opposite of highly rigid crystalline polyolefins such as polypropylene and polyethylene.

In the present invention, crystalline polyolefin resins are polymers with relatively high crystallinity, such as polyethylene, polypropylene, and polybutene-1, and copolymers containing ethylene or propylene as the main component, and other polymers containing polyolefin as the main component. Also included are mixtures with resins.

These polymers may be crosslinked, and crosslinking is preferred when particularly strong mechanical properties are required.
Crosslinking methods include electron beam irradiation crosslinking, organic peroxide crosslinking,
Various methods such as crosslinking using silane or azide can be employed. There are no particular restrictions on the inorganic filler, but those with good dispersibility and a uniform and fine particle distribution are preferable. In particular, calcium carbonate, aluminum hydroxide, and gypsum powder are preferably used. The type of inorganic filler is selected depending on the properties expected of the malleable composite resin material obtained. For example, when it is desired to impart flame retardancy, a hydrated salt such as aluminum hydroxide is used. The content ratio of the inorganic filler is important because it is closely related to the properties of the resulting flexible composite resin material. Usually 15-70
%, preferably 20 to 60%.

If the inorganic filler content is less than 15%, a composite resin material that can fully exhibit the characteristics of the present invention cannot be obtained, while if it exceeds 70%, the mechanical strength of the resulting composite material will be extremely poor, making it impractical. In the present invention, the inorganic filler is treated with a titanate coupling agent as described above.

The titanate coupling agent is a monoalkoxy organic titanate compound, such as isopropyl-triisostearoyl titanate, isopropyl-isostearoyl dimethacrylic titanate, isopropyl-isostearoyl diacryl titanate, isopropyl-tri(diisooctyl) phosphate)-titanate, isopropyl-tri(dioctylpyrophosphate)-titanate, and the like. Among them, isopropyl triisostearoyl titanate is most preferably used.
Usually 0.5 to 3 parts by weight of 10 parts by weight of inorganic substance. It is added in a proportion of parts by weight. Further, various additives such as a crosslinking agent, an antioxidant, an ultraviolet absorber, and a coloring agent may be added as required. The method for producing the crystalline polyolefin resin composite resin material having flexibility of the present invention includes:
For example:

First, inorganic particles are treated with a titanate coupling agent, and the inorganic particles are mixed with a polymer in a desired ratio.

Kneading is usually done in rolls or in a bunbury. This mixed wire material is formed into a sheet shape by calender molding, extrusion molding, or press molding. Next, some external stimulus is applied to this sheet molded product to destroy the interfacial bond between the polymer matrix and the inorganic particles. There are various methods of applying this external stimulus, and one effective method is, for example, applying bending deformation. That is, a method in which a composition molded body is passed between a plurality of grooved rolls to locally apply bending deformation to the molded body and finally cause interfacial fracture over the entire surface, or a method in which the sheet itself has an uneven structure immediately after sheet forming. A method of applying bending deformation locally to the uneven portions by passing this molded product through a smooth roll, or by continuously moving it along a rotating roll surface with a small radius of curvature. For example, a method of imparting slight bending deformation.
By combining these steps, a flexible composite resin material that is softened over the entire surface of the sheet can be obtained.
Although the malleable composite resin material of the present invention is based on crystalline polyolefin resin, it is a unique material that is flexible and malleable. It can be used in various fields as interior and exterior bag material parts for buildings and as a European sheet material as a substitute for rubber, and its utility value is extremely high.

The invention will be illustrated with reference to the following examples.

Example 1 4 parts by weight of commercially available crystalline polypropylene resin (specific gravity 0.91, melt index 10) and commercially available unsurface-treated ground calcium carbonate (specific gravity 2.7, average particle size 1
．． A composition consisting of 6 parts by weight of treated calcium carbonate obtained by adding 3 parts by weight of isopropyltri(isostearoyl) titanate to 10 parts by weight of 10 parts by weight and stirring well was kneaded with an open roll. Thereafter, it was formed into a sheet with a thickness of 1 by hot pressing.

When the obtained sheet was subjected to bending deformation with a radius of curvature of 1 and folded, stress whitening occurred in the deformed portion, and this portion became significantly soft. By applying such an operation to the entire surface of the sheet, a sheet material that is soft over the entire surface, extremely flexible to bending and twisting deformation, and highly maneuverable was obtained. When a short fence shape 4 piece of 20 x 7 length is cut out from the above sheet material and twisted so that both ends are perpendicular to each other, it is easily deformed and retains its shape, showing almost no restoring force. There wasn't.

Furthermore, when the sheet material was immersed in liquid nitrogen, frozen and fractured, and its cross section was observed using a scanning electron microscope, it was found that the calcium carbonate particles were well dispersed, and the surface of most of the particles was It was observed that it was separated from the polymer.

The above operation was carried out by changing the mixing ratio of polymer and treated calcium carbonate as shown in Table 1.

Table 1 In the above Table 1, "unbreakable" means that there was no abnormality such as breakage even after bending deformation of one fence with a radius of curvature, and a soft material was finally obtained.

Moreover, "breaking" refers to a case where breakage occurs and the material does not become a fertilized material after all. Comparative Example 1 In Example 1, when commercially available calcium carbonate was used as it was without being treated, the sheet broke due to bending deformation and a soft material could not be obtained.

Examples of changing the mixing ratio of calcium carbonate are shown in Table 1 above.
They are summarized in the "No treatment" column. In case of filler concentration 2 anchor part,
Regardless of whether surface treatment was applied or not, there was no breakage, but softening was also difficult to occur. When a short fence-shaped piece measuring 20 x 7 squares was cut out from this sheet and subjected to the same twisting deformation as above, it was difficult to deform and immediately returned to its original shape when the external force was removed. Example 2 5 parts by weight of commercially available high-density polyethylene resin (specific gravity 0.96, melt index 5.0) and 100 parts by weight of commercially available aluminum hydroxide (specific gravity 2.4, average particle size 0.9 French) were added. treated aluminum hydroxide treated with 1 part of isopropyl tri(isostearoyl) titanate
parts by weight were kneaded and molded into a sheet with a thickness of 3 skins.

Bending deformation with a radius of curvature of 1 inch or more was applied over the entire surface of this sheet. As a result of this treatment, the sheet had excellent flexibility and properties, could be easily deformed by a slight external force, and was similar to a flexible rubber that did not recover from the applied deformation immediately. Comparative Example 2 A sheet with a thickness of 3 sails was obtained in the same manner as in Example 2, except that aluminum hydroxide treated with y-methacryloxypropyltrimethoxysilane was used.

Similarly, when bending deformation with a radius of curvature of one rib or more was applied to the entire surface of this sheet, the sheet easily broke and did not become a flexible material. Comparative Example 3 The commercially available heavy calcium carbonate 3009 used in Example 1 was suspended in 120% water, and 90% of stearic acid was added to this suspension, thoroughly stirred, and then heated to 80°C. The water was evaporated and the mixture was sufficiently dried to produce stearic acid-treated calcium carbonate.

When a sheet with a thickness of 1 sail is made from a composition consisting of 4 parts by weight of the polypropylene resin used in Example 1 and 60 parts by weight of the stearic acid-treated calcium carbonate obtained above, and a similar bending deformation is applied to this sheet. , the sheet was folded and did not form a good soft material.

Example 3 Parts by weight of commercially available low density polyethylene (density 0.92 mm/base, melt index 1.0) 3 parts by weight of the treated calcium carbonate 7 used in Example 1 and dicumyl peroxide After roll-kneading the composition consisting of 1 part by weight, it was formed into a sheet with a thickness of 10 legs by hot pressing, and at the same time was heated to a temperature higher than the decomposition temperature of dicumyl peroxide to crosslink the formed composition. I had it processed.

When the obtained crosslinked sheet was stretched approximately three times by a stretching machine, a very flexible and flexible rubber-like sheet having a thickness of 7 ribs was obtained. This sheet is extremely pliable.
It did not break even when folded at 80 degrees.

Claims (1)

[Claims] 1 Consists of a crystalline polyolefin resin and 15 to 70% by volume inorganic particles whose surface has been treated with a titanate coupling agent, and the interfacial adhesion between the resin and the inorganic particles is substantially broken. A crystalline polyolefin resin composite material characterized by: