JPS591302B2 - Synthetic resin composition for lacquerware base - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synthetic resin composition for lacquerware substrates that has good paintability.

More specifically, the present invention relates to a synthetic resin composition for lacquerware base comprising polypropylene, calcium carbonate, and dried wood flour. Traditionally, lacquerware such as trays, bowls, sets, jubako, tea cups, and other kitchen and dining utensils have been made of wood as their base material, but in recent years, phenolic resin and melamine have been used for reasons of mass production and cost. Thermosetting resins such as resins and urea resins, and thermoplastic resins such as nylon resins and ABS resins have come to be partially used as substitutes for wood.

However, phenolic resins and melamine resins generally have low mechanical strength such as impact strength, making it difficult to mass-produce them, and urea resins have health and hygiene problems due to the generation of formaldehyde when handled, as well as damage and damage. It has the disadvantage of being easily deformed. In addition, nylon resin and ABS resin are easily deformed by heat due to hot water, etc., and are also difficult in terms of price, and these synthetic resins have not yet reached the point where they can fully replace wood as a base for lacquerware. Moreover, some of these synthetic resin materials have the disadvantage that they may generate harmful gases when incinerated during disposal. Furthermore, when these synthetic resin materials are used, deburring after molding is not easy.

In other words, in the case of thermosetting resins, deburring is done with sandpaper after molding, but this is a difficult task, and in the case of thermoplastic resins, deburring is done with sandpaper. If this is done, the surface of the molded body may become roughened or the surface of the molded body may be deformed due to frictional heat, so it cannot be used, and therefore it is decided to deburr with a knife. However, this method alone has the disadvantage that it is difficult to obtain a smooth surface. Here, the present inventors have developed a synthetic resin material that improves the drawbacks of various synthetic resins used as a lacquerware base, is mass-producible, is inexpensive, and has other sufficient physical properties as a lacquerware base. ,
As a result of various searches and studies, polypropylene 30 to 6
It has been found that a synthetic resin composition containing 0% by weight, 30 to 50% by weight of calcium carbonate, and 10 to 30% by weight of dry wood flour is most suitable as a lacquerware base.

That is, when the synthetic resin composition of the present invention is used as a lacquerware base, deburring after molding can be done extremely easily with sandpaper, and as in the case of conventional wood bases). There is no need to perform rusting work using a saw, etc., and work efficiency is significantly improved.

Moreover, the lacquerware base according to the present invention has a characteristic that it is particularly difficult to cause thermal deformation.

It has been found that when polypropylene is used alone as a lacquerware base, the rigidity, surface hardness, and adhesion strength of paint are significantly inferior to those of wood bases.

Therefore, in order to improve these drawbacks, the present inventors added calcium carbonate in the hope of improving rigidity and surface hardness, and added wood in the hope of improving paintability. When these powders were added to polypropylene at the same time, it was discovered that these powders had good affinity with polypropylene, and within the range of the mixing ratio described above, exhibited extremely suitable physical properties as a lacquerware base. The polypropylene used in the present invention includes not only commercially available general products but also copolymers containing propylene as a main component with ethylene or the like. Calcium carbonate is 100 to 250 mesh, and wood flour is dried maple, cedar, white birch, etc., and the moisture content is 80 to 7% by weight. 200 mesh is suitable as a component of the synthetic resin composition of the present invention. Particularly suitable mixing ratios for the synthetic resin composition for lacquerware bases of the present invention are 40 to 45% by weight of polypropylene, 35 to 40% by weight of calcium carbonate, and 15 to 20% by weight of dry wood flour.

Increasing the amount of calcium carbonate or dry wood flour used is advantageous in terms of price, but it is also undesirable because it causes poor moldability and reduces the impact strength of the product.
As the synthetic resin composition of the present invention, depending on the shape of lacquerware,
In particular, when it is necessary to improve the moldability, in order to improve the fluidity of the synthetic resin composition during melting, for example, atactic polypropylene with a molecular weight of 250
00 to 35,000, 3 to 5% by weight
It should be added so that

Furthermore, if it is desired to particularly increase the surface hardness of the lacquerware base, an appropriate amount of talc may be added. The synthetic resin composition of the present invention is produced by kneading the above-mentioned mixture using a kneader at 180 to 200'C for about 1 minute, and then forming it into pellets using an extruder and a pelletizer. A lacquerware base of any shape can be obtained by injection molding at about 180 to 220°C.

It goes without saying that the molded lacquerware base can be used as is or used as various containers, but for a paint finish, an undercoat material such as polyurethane is first applied, and then epoxy or polyurethane paint is applied. Finished with lacquerware by applying natural lacquer. Next, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 4 As the polypropylene, pellets of Tokuso Polypropylene Ml2L manufactured by Tokuyama Soda Co., Ltd., 180 mesh of calcium carbonate powder, and 100 mesh of dry wood powder obtained from the woody part of Toga, or further molecular weight 25,000 Atactic polypropylene pellets of
The mixture is melted and kneaded at 00°C for 1 minute, then passed through an extruder and pelletized using a pelletizer.

Using this pellet, injection molding is carried out and
A plate-shaped test piece of 7XU, width 150mTfL, and thickness 3.2mm is prepared. Various mechanical properties of the obtained test piece were measured. Furthermore, Micron manufactured by Kashiyuichi Co., Ltd. was applied to the obtained test piece as an undercoat material.
To finish, I applied vermilion HG coat from Chukoku Toyo Co., Ltd. The painted surface is cut into a 1mm base grain pattern, and Zero Tape is pasted on top of it. When the Zero Tape is removed, the paint film peels off or not to determine the adhesion strength of the paint and determine whether the paintability is good or bad. did. These results are shown in Table 1. As is clear from the above table, it can be seen that the test pieces according to the present invention can be satisfactorily used as lacquerware bases in terms of their mechanical properties and paintability.

Claims (1)

[Claims] 1 30 to 60% by weight of polypropylene, 30 to 50% by weight of calcium carbonate, and 10 to 30% by weight of dry wood flour.
A synthetic resin composition for lacquerware base, which is made by adding % by weight.