JP2003189935A - Toothbrush - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothbrush having excellent usability and feel to use as a toothbrush, and excellent transparency. <P>SOLUTION: This toothbrush comprises a toothbrush main body 10 comprising a head part 12 to fix bristles, a handle part 11, and a neck part 13 connecting these. At least a part of the toothbrush main body 10 is formed of resin comprising ethylene-propylene random copolymer. The mixed ratio of polyethylene parts in the resin is 3-6 wt.%, and the modulus of bending elasticity of the resin is 900-2000 MPa. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothbrush,
In particular, the present invention relates to a toothbrush made of a material which is excellent in usability and usability as a toothbrush and has a certain degree of transparency. 2. Description of the Related Art In general, as shown in FIG. 1, a toothbrush includes a toothbrush main body 10 having a grip portion 11 and a head portion 12 having a neck portion 13 which provides an appropriate elasticity.
A brush 14 is planted on 2. For the brush 14, a polyamide resin (nylon 6-10, nylon 6-12) or polybutylene terephthalate (PBT) resin is generally used. The toothbrush body 10 includes polypropylene, polyethylene, polyethylene terephthalate, polybutylene terephthalate, polymethyl methacrylate, cellulose cellulose propionate, polyurethane, polyamide, A
Resins such as BS are used. When it is desired to provide a clean feeling to the body of the toothbrush as a transparent material, for example, if a polypropylene resin is used, there is a problem that the transparency of the thick portion of the toothbrush becomes poor with propylene alone. Further, various materials are used for the material of the toothbrush body 10 in order to improve strength, transparency and the like. For example, Japanese Patent Application Laid-Open No. 2000-125936 discloses a toothbrush which is blended with a specific polyester resin, has excellent transparency, does not have sink marks and whitening, and has excellent flexibility and chemical resistance. In Japanese Patent Application Laid-Open No. Hei 7-165988, a methacrylic resin containing a specific rubbery copolymer is used to improve transparency, impact resistance, and rigidity. In Japanese Patent Application Laid-Open No. 2000-41737, a glossy handle is formed by forming a gap between the handle of the toothbrush body and the transparent resin exterior body.
As the transparent resin, polyethylene terephthalate (PE
T), acrylonitrile-styrene (AS) resin, and polymethyl methacrylate (PMMA) are exemplified. Incidentally, as a method of fixing the brush to the head portion of the toothbrush, there is a general method of fixing the brush using a metal piece (flat wire). Other fixing methods include an in-mold method of manufacturing a toothbrush by heating a lower end of a brush or a bundle of brushes to form a molten mass and then injecting a molten resin into a mold, or a method of melting a brush bundle. For example, there is a heat fusion method of melting the portion and press-fitting it into the flocked hole of the head portion of the toothbrush to fix it. [0008] Toothbrushes are used as cleaning tools in the oral cavity, and use not only materials that are excellent in safety, but also no breakage of the neck due to tooth brushing pressure during brushing. As described above, the toothbrush body is required to have a rigid structure and a resin property having a certain strength and chemical resistance. As the material of the toothbrush main body, polypropylene resin is generally used from the viewpoints of cost, productivity and the like. However, polypropylene resin has a problem in its own transparency. When a single polypropylene resin is used for a thick-walled product such as a toothbrush body, a problem occurs in transparency, and other relatively expensive resins are used. There is a technical problem that there is a drawback that the design property is inferior to that of a toothbrush using, and poor appearance discrimination. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a toothbrush which is excellent in usability and usability as a toothbrush and which is excellent in transparency. It is. [0011] The present invention has solved the above-mentioned problems, and a first aspect of the present invention is a toothbrush including a head for fixing a brush, a grip, and a neck for connecting the same. At least a part of the main body is a resin composed of an ethylene / propylene random copolymer, the mixing ratio of the polyethylene portion of the resin is 3 to 6% by weight, and the flexural modulus of the resin is 900 MPa to 2000 MPa. It is a toothbrush characterized by the above-mentioned. According to the first aspect of the present invention, at least a part of the toothbrush main body including the head portion for holding the brush, the grip portion, and the neck portion connecting them is made of a resin made of an ethylene / propylene random copolymer. By setting the mixing ratio of the polyethylene portion of the resin made of the copolymer in the range of 3 to 6% by weight, at least a part of the toothbrush body can be made of a more transparent material. If the mixing ratio of the polyethylene portion is less than 3% by weight or more than 6% by weight, transparency and other problems will occur. Preferably, the mixing ratio of the polyethylene portion is in the range of 3.5 to 4.5% by weight. On the other hand, by injecting and forming the toothbrush main body with a resin made of such a material, the toothbrush main body is injection-molded with a resin made of an ethylene / propylene random copolymer. Is a polymer having an irregular arrangement order, that is, a random copolymer, so that the molded product has improved properties such as mechanical properties and elasticity. The flexural modulus of the resin composed of the ethylene / propylene random copolymer is preferably in the range of 900 MPa to 2,000 MPa. When a resin having a lower value is molded into a toothbrush, the neck has poor stability and is hardly brushed. However, there is a problem that the composition is hardly deformed, but is easily broken when an excessive force is applied. The flexural modulus is a value obtained by a test method specified in JIS K7203. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 (a)
1 is a perspective view showing an embodiment of a toothbrush of the present invention, and FIG. 1B is an enlarged view of a head portion of the toothbrush. As shown in FIG. 1A, the toothbrush according to the present embodiment has a toothbrush body 10 having a grip portion 11, a head portion 12, and a neck portion for giving the grip portion 11 and the head portion 12 an appropriate elasticity. 13 and the head 12
The brush 14 is planted on the surface. The toothbrush body 10 is at least partially made of a resin made of an ethylene / propylene random copolymer. The resin of the ethylene / propylene random copolymer has a mixing ratio of the polyethylene portion of 3 to 6% by weight, and more preferably 3.5 to 4.5% by weight. The polypropylene portion is approximately 97-94% by weight. That is, the whole of the toothbrush body 10 may be formed of a resin made of an ethylene / propylene random copolymer, or only the head portion 12 and the grip portion 11, or from the head portion 12 to the neck portion 13, or the neck portion. Thirteen
Therefore, the gripper 11 may be made of a random copolymer.
Furthermore, the toothbrush main body 10 may be formed by two-color molding of a propylene resin and an ethylene / propylene random copolymer, or may be made of another resin such as an olefin resin, a styrene resin, or a urethane resin. Two-color molding in combination with a plastic elastomer may be used. On the other hand, the head portion 1 of the toothbrush of the present embodiment
2, the thickness A is set to 2.5 to 6 mm, more preferably,
2.8 to 5.0 mm. Further, as a preferable value in terms of the strength of the head portion 12, the thickness A in the vicinity of the tip is 4.5
mm, and the thickness B near the rear end of the head portion 12 is set to 5.0.
mm. The thickness C of the neck portion 13 is set to 4 to 7 mm, more preferably 4.5 to 5.5 mm. On the other hand, the brush 14 is made of a polyamide resin (nylon 6-10, nylon 6-12) or a polyester (polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polybutylene terephthalate (PBT)) resin. . Although the thickness of the hair is not particularly limited, it is usually 6 mil (0.152).
4 mm) to 11 mil (0.2794 mm) are used. Further, the shape of the brush 14 is not particularly limited, but a general shape such as a flat cut, a mountain cut and a ship bottom cut is used. On the other hand, the method of fixing the brush or the brush bundle to the head-planted surface may be a method of fixing using a metal piece (flat wire) as generally performed in a method of manufacturing a toothbrush. Alternatively, an in-mold method may be used in which the lower end of the brush or the brush bundle is heated to form a molten mass, and then the molten resin is injected into a mold to manufacture a toothbrush. Furthermore, a heat fusion method of manufacturing a toothbrush by melting the brush fusion portion and pressing it into the toothbrush head portion flocked hole and fixing it may be used. Furthermore, a method of bonding a brush or a bundle of brushes to the head portion may be used. The toothbrush of the present invention may be manufactured by any of these methods, but the in-mold method or the heat fusion method is more preferable than the method of manufacturing using a metal piece from the viewpoint of waste treatment. The toothbrush body 10 is molded from a resin composition of an ethylene / propylene random copolymer having a mixing ratio as described above by a commonly used injection molding method. In this toothbrush, the bending elastic modulus of the toothbrush main body 10 is 900 MPa to 2000 MPa, and the usability and feeling of use as a toothbrush can be improved. The flexural modulus is determined by a test method specified in JIS K7203. The toothbrush of the present invention has a toothbrush body formed of a resin made of an ethylene / propylene random copolymer, and has improved elasticity and breakage resistance as compared with those formed of a polypropylene monomer. It became favorable. As described above, according to the present invention,
At least a part of the toothbrush body is made of a resin made of an ethylene / propylene random copolymer, and even a thick portion of the toothbrush body can be made of a transparent material, giving the toothbrush a clean feeling and the like. In addition, it is possible to provide a variety of designs and is effective in differentiating the design of the toothbrush. Further, according to the present invention, since the resin forming a part or the whole of the toothbrush body is a resin obtained by random copolymerization, the toothbrush body can be given an appropriate elasticity and can be used as a toothbrush. There is an advantage that it can be excellent in properties and usability.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (a) is a perspective view for explaining a toothbrush,
(B) is a side view of the tip. [Description of Signs] 10 Toothbrush main body 11 Gripping part 12 Head part 13 Neck part 14 Brush

Claims (1)

Claims 1. At least a part of a toothbrush body comprising a head portion for fixing a brush, a grip portion, and a neck portion connecting them, is a resin made of an ethylene / propylene random copolymer. The mixing ratio of the polyethylene portion is 3 to 6% by weight, and the flexural modulus of the resin is 900 MPa to 2
000 MPa.