JP2008173902A - Fabrication method of structure with sheet or molded object made of vegetable-derived raw material resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fabrication method of a structure with a sheet or a molded object made of a vegetable-derived raw material resin without the generation of resin cracking or a whitening phenomenon, in bending or incorporating such a structure. <P>SOLUTION: This method is to bend or incorporate the structure with the sheet 11 or the molded object which is made of a vegetable-derived raw material resin. That is, the resin located in a fabrication region, is fabricated while being heated at a glass transition temperature or above and less than a crystallization temperature, of the resin, and then, forcibly cooled at less than the glass transition temperature. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for processing a structure having a sheet or molded product made of plant-derived raw resin.

  When processing a structure having a sheet or molded product made of resin, a processing method of “bending while stretching” or “bending while pressing” is often used for the sheet or molded product made of resin. In such a processing method, the sheet or the molded product is required to have fairly severe processing resistance.

  For example, assembling that involves bending such as winding a sheet structure with a resin sheet bonded to the base material around the core, or striking to fit the structure with the resin sheet bonded to the surface without gaps Processing etc. are mentioned.

  By the way, in recent years, plant-derived material resins represented by polylactic acid made of plant-derived materials have attracted attention in consideration of the environment. These plant-derived raw material resins are very brittle as they are and have low mechanical properties such as impact resistance. For this reason, studies on the modification of plant-derived raw material resins are underway, and physical properties have been modified based on technologies that promote crystallization of plant-derived raw material resins by the addition of molding methods such as stretching and crystal nucleating agents. It's getting on.

  However, even if the sheet or molded product is made of plant-derived raw material resin that is being modified, if it is subjected to severe processing such as “bending while stretching” or “bending while pressing” as described above However, the problem of cracking and whitening has not been solved. Even if bending or incorporating with heating to soften the plant-derived material resin in order to avoid cracking, relatively many amorphous parts remain in the plant-derived material resin, so cooling In this stage, the whitening occurs as crystallization progresses.

  The present invention has been made in view of the circumstances as described above, and when bending or incorporating a structure having a sheet or molded product made of a plant-derived material resin, the resin at the processing site is cracked or whitened. An object of the present invention is to provide a processing method that does not generate the problem.

  In order to solve the above-mentioned problems, the present invention firstly is a method of bending or incorporating a structure having a sheet or molded product made of a plant-derived raw material resin, wherein After processing while heating to a temperature above the glass transition temperature and below the crystallization temperature, the resin at the processing site is forcibly cooled below the glass transition temperature.

  Secondly, after bending or assembling, the resin at the processing site is forcibly cooled to less than its glass transition temperature within 3 minutes.

  Third, the plant-derived material resin is polylactic acid.

  According to the said 1st invention, a bending process or an incorporating process can be performed, without generating the crack and whitening of the sheet | seat or molded object which consist of plant-derived raw material resin.

  According to the second invention, it is possible to perform bending or assembling more preferably in the first invention.

  According to the third aspect of the invention, polylactic acid is the most well-known plant-derived raw material resin, and there are more data for modification of polylactic acid than other plant-derived raw material resins, and it is easy to obtain. It can be used suitably.

  Embodiments of the present invention will be described below.

  The plant-derived raw material resin in the present invention is a resin synthesized from plant-derived raw materials, and may be either a synthetic product or an artificial synthetic product. For example, polyhydroxyalkanoic acids (PHA) such as polyhydroxybutyric acid synthesized by microorganisms as synthesized by organisms by fermentation, etc., polylactic acid from lactic acid, polyglycol from glycolic acid as artificially synthesized Examples of polyesters such as acids and natural products include starch. Among them, polylactic acid which is most widely distributed as a product and has abundant research data can be suitably used. Furthermore, in addition to the plant-derived raw material resin itself, other components may be chemically introduced into the plant-derived raw material resin skeleton by copolymerization, or a plurality of plant-derived raw material resins or resins other than plant-derived raw material resins and plant-derived raw material resins Or additives such as impact strength modifiers and crystal nucleating agents may be included, and any additives can be used as long as they do not interfere with workability by heating and cooling.

  In addition, since sheet cracking is a particularly significant problem when plant-derived raw resin is used as a sheet, the present invention includes a sheet or molded product made of plant-derived raw resin in order to clarify that the sheet is included. The molded product is not particularly limited as a shape other than the sheet, and includes, for example, a simple cylindrical extrusion shape, a complicated profile extrusion shape, and the like.

  The structure having a sheet or molded product made of plant-derived raw material resin in the present invention is not only a sheet or molded product itself made of plant-derived raw material resin, but also a sheet or molded product made of plant-derived raw material resin, Structures combined with other materials by adhesion, fitting, etc. are also included, for example, structures obtained by adhering plant-derived raw resin as a decorative sheet to a substrate of another material, and made of plant-derived raw resin The shape, structure, etc. are not limited as long as the resin part having a sheet or molded product is a structure that becomes a processed part.

  In the present invention, when bending or incorporating a structure having a sheet or molded product made of a plant-derived raw material resin, first, the processed part is heated to a temperature higher than the glass transition temperature of the plant-derived raw material resin and lower than the crystallization temperature. Process. For example, polylactic acid generally has a glass transition temperature of 60 ° C. or higher and a crystallization temperature of less than 110 ° C. The heating method is not particularly limited, and examples thereof include heating with a hot wire heater, a light, a hot air blower, and the like. Then, it may be heated locally only to the resin or the entire structure may be heated, and the heating method and the like are not particularly limited as long as at least the processing site is in the temperature range. By heating in the above temperature range, bending processing or incorporation processing in a softened state can be performed, so that processing while preventing cracks and the like is possible.

  Next, after bending or assembling, the resin at the processing site is forcibly cooled to below its glass transition temperature. For example, in the case of polylactic acid, the glass transition temperature is set to less than 60 ° C. Here, the forced cooling in the present invention is used to mean that the cooling is artificially performed faster than the natural cooling. The cooling method is not particularly limited, and examples thereof include a spot cooler and a cooling method using cold water. By forcibly cooling immediately after processing, crystallization of the non-crystalline portion remaining in the plant-derived raw material resin can be prevented, and whitening of the sheet or molded product can be prevented. In addition, as time to cooling in this invention, although the crystallization speed changes with kinds, the ratio of an amorphous part, etc. of plant origin raw material resin to be used, generally glass of plant origin raw material resin is within 3 minutes. It is preferable to cool to less than the transition temperature, more preferably within 1 minute, crystallization progresses over time, and white cooling occurs when natural cooling occurs.

  Accordingly, examples will be described below. Of course, the invention is not limited by the following examples.

<Fabrication of sheet frame door frame>
FIG. 1 is a side perspective view of a sheet-attached door frame member before processing, and FIG. 2 is a side view of the sheet-attached door frame member after processing.

  As shown in FIG. 1, a sheet 11 formed by sheet molding (sheet thickness: 30 μm) of a commercially available polylactic acid (manufactured by Mitsui Chemical Co., Ltd., Lacia) as a plant-derived raw resin is used as an MDF substrate 12 (plant fiberboard, JIS A The structure 1 was produced by laminating the surface of 5950 compliant, thickness: 4 mm) and V-cutting the back side (MDF side) to form the groove 13. Thereafter, the structure 1 is bent in the direction of the arrow in FIG. 1 so as to fold the groove 13 and wound around the plywood core material 2 to form a sheet-attached door frame material 3 (width: 150 mm) as shown in FIG. , Thickness: 30 mm). Here, a modifying material (manufactured by Mitsubishi Rayon Co., Ltd., Metabrene) was added to polylactic acid, and an ethylene vinyl acetate adhesive was used as an adhesive during lamination.

  The conditions at the time of bending and the presence or absence of cracking and whitening of the sheet in the appearance after bending were confirmed visually and evaluated by ○ ×. The evaluation results are as shown in Table 1.

なお、曲げ加工時の条件は以下のとおりである。

In addition, the conditions at the time of a bending process are as follows.

<Example 1>
Heating set temperature (hot air heater): 70 ° C
Heating time 1 minute (sheet surface temperature: 65 ° C)
Cooling set temperature (vortex cooler): 15 ° C
Cooling time 1 minute (sheet surface temperature: 18 ° C.)
<Comparative Example 1>
Heating set temperature (hot air heater): 70 ° C
Heating time 1 minute (sheet surface temperature: 65 ° C)
Cooling: Natural cooling (15 minutes to room temperature 22 ° C)
<Comparative example 2>
No heating or cooling <Comparative Example 3>
Heating set temperature (hot air heater): 125 ° C
Heating time 1 minute (sheet surface temperature: 120 ° C)
No cooling (cooling was not performed due to significant deformation of the sheet due to heating)
From the above results, bending is performed at a glass transition temperature (57 ° C.) or higher and a crystallization temperature (110 ° C.) or lower, and immediately after the processing, the sheet 11 is cooled to a glass transition temperature (57 ° C.) or lower to crack. It can be seen that the processing can be performed without causing whitening.

It is a side perspective view before processing of a sheet pasting door frame material. It is a side view after processing of a sheet pasting door frame material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Structure 11 Sheet 12 MDF base material 13 Groove 2 Plywood core material 3 Sheet pasting door frame material

Claims (3)

  A method of bending or embedding a structure having a sheet or a molded product made of plant-derived raw material resin, and processing after processing the resin at the processing site to a temperature higher than its glass transition temperature and lower than its crystallization temperature. A method of processing a structure having a sheet or a molded article made of a plant-derived raw resin, wherein the resin at the site is forcibly cooled below its glass transition temperature.   The structure having a sheet or a molded article made of a plant-derived raw material resin according to claim 1, wherein the resin at the processing site is forcibly cooled to less than its glass transition temperature within 3 minutes after bending or assembling. Body processing method.   The method for processing a structure having a sheet or a molded product made of a plant-derived raw material resin according to claim 1, wherein the plant-derived raw material resin is polylactic acid.

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