JP2000125936A - Handle for tooth brush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a handle for tooth brushes which is excellent in transparency, is free from the shrinkage and whitening of molded goods, is excellent in curving properties and chemical resistance and may be inexpensively manufactured. SOLUTION: This handle for tooth brushes consists of a polyester resin. This polyester resin, thereupon, consists essentially of the structural unit expressed by general formula (1) and the structural unit expressed by general formula (2) and is so compounded that the ratio of (1)/(2) attains 95 to 85 wt.%/5 to 15 wt.% when the entire part is defined as 100 wt.%. In the formulas, Ar1 and Ar2 denote benzene rings and the benzene rings may be substituted with alkyl groups or halogen atoms. X denotes a methylene group, sulfonyl group, carbonyl group, cyclohexylene group, sulfur atom or oxygen atom and the hydrogen atom of the methylene group may be substituted with a methyl group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a handle for a toothbrush, and more particularly to a handle for a toothbrush which is excellent in transparency, does not have sink marks and whitening, and has excellent flexibility and chemical resistance.

[0002]

2. Description of the Related Art Toothbrush handles are required to have chemical resistance which does not deteriorate even when they come into contact with chemicals such as toothpaste powder during use. For this reason, conventionally, polypropylene resins are generally used for toothbrush handles because of their chemical resistance and low cost.
However, only an opaque toothbrush handle made of this polypropylene resin can be manufactured, and in recent years, a demand for design has increased, so that a transparent toothbrush handle has been demanded.

For satisfying such requirements, for example, acrylic resin, polycarbonate resin, transparent ABS
A toothbrush handle made of resin has been proposed. However, toothbrush handles made of these resins are excellent in transparency but are inferior in chemical resistance as described above. For example, when used for a long time with toothpaste powder adhered thereto, cracks are likely to occur in actual use. There is a problem.

A toothbrush handle made of polyethylene terephthalate (hereinafter referred to as "PET") resin has also been proposed. A toothbrush handle made of PET resin is excellent in chemical resistance and has transparency.
However, there is a problem that the molded product is inferior in moldability, and the obtained molded product is liable to have so-called sink marks in which a part of its surface is dented or to be easily whitened. In order to prevent whitening, it is necessary to cool the mold by lowering the mold temperature to about 15 ° C. during molding, but this complicates the manufacturing process and increases the cost.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and is excellent in transparency, without sinking or whitening of a molded product, excellent in flexibility and chemical resistance, and can be manufactured at a low cost. Is provided.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention is a handle for a toothbrush made of a polyester resin, wherein the polyester resin has a structural unit represented by the following general formula and a structural unit represented by the following main components, and the entirety is 100 wt%.
The gist of the present invention is a toothbrush handle, wherein the ratio of / is 95 to 85 wt% / 5 to 15 wt%.

[0007]

Embedded image

The present invention also relates to a toothbrush handle made of a polyester resin, wherein the polyester resin has a structural unit represented by the above-mentioned general formula and a structural unit represented by the above-mentioned main component as a main component, and the whole is 100 wt%. ,
The gist of the present invention is a toothbrush handle, wherein the ratio of / is 95 to 85 wt% / 5 to 15 wt%.

Further, the present invention relates to a toothbrush handle made of a polyester resin, wherein the polyester resin contains, as a main component, a structural unit represented by the structural unit represented by the above general formula. , Assuming that the whole is 100 wt%, the ratio of // is 90-80.
The gist of the present invention is a toothbrush handle characterized by being blended so as to be wt% / 5 to 15wt% / 5 to 15wt%.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The toothbrush handle of the present invention is
It must be made of polyester resin. As the polyester resin, the structural unit represented by the above general formula and the structural unit represented by the above-mentioned general formula are used as main components, and the ratio of / is 95 to 85 wt% / 5 to 15 wt% with the whole being 100 wt%.
% Polyester resin (hereinafter referred to as "polyester A") is used. The structural unit represented by the general formula is a substance having excellent chemical resistance and transparency, but with this alone, sinkage or whitening easily occurs when formed into a molded product. In addition, by blending the structural unit represented by the above general formula, it is possible to obtain a molded article having a good appearance which has solved the above problems.

If the proportion of the structural unit represented by the general formula exceeds 95% by weight, sink marks and whitening occur, and a good molded product cannot be obtained. If the ratio is less than 85 wt%, the chemical resistance will be poor.

Also, the toothbrush handle of the present invention comprises, as a main component, a structural unit represented by the above-mentioned general formula instead of the above-mentioned polyester A, and the whole is 1 unit.
Assuming 00 wt%, the ratio of / is 95 to 85 wt% /
A polyester resin (hereinafter, referred to as “polyester B”) blended to be 5 to 15 wt% may be used.

The structural units represented by the general formula are the same as those used in polyester A, and the effects are the same. In addition, the structural unit represented by the general formula is, like the structural unit represented by the general formula, one that hardly causes sink and whitening of a molded product, but the structural unit represented by the general formula is represented by the general formula. Polyester B also has the advantage of lower cost than Polyester A because it is cheaper than the structural unit.

The ratio of the structural units represented by the general formulas and is represented by the following formula:
It is necessary to set t% / 5 to 15 wt%. If the ratio exceeds 95 wt%, sinking and whitening occur as in the above, and a good molded product cannot be obtained.
If the amount is less than 5% by weight, the molded article becomes brittle and has poor chemical resistance.

Further, the handle for a toothbrush according to the present invention comprises:
In place of the polyester A or the polyester B, a structural unit represented by the structural unit represented by the general formula and a structural unit represented by the general formula are used.
wt%, the ratio of // is 90-80 wt% /
Polyester resin blended to be 5 to 15 wt% / 5 to 15 wt% (hereinafter referred to as "polyester C").
May be formed. With such a configuration, a toothbrush handle having excellent transparency, less sink marks and whitening, and excellent flexibility and chemical resistance can be obtained. In addition, there is an advantage that brittleness can be improved as compared with the above polyester B.

The polyester A in the present invention is usually obtained by using PET or a polyester mainly composed of PET and polyarylate (hereinafter referred to as "PAR") at a required ratio.

Specifically, as a method for producing the polyester A, PET or a polyester mainly composed of PET, a PAR and a catalyst are charged into a reactor and melt-heated under reduced pressure to cause a transesterification reaction. There is a method in which the mixture is discharged from the reactor at the completion of the reaction to form pellets. On this occasion,
As the catalyst, it is preferable to use an alkali metal compound such as sodium acetate, sodium hydroxide and potassium hydroxide.

Further, PET or a polyester mainly composed of PET, PAR and the above-mentioned catalyst are mixed by using various blenders such as a turn-blender and then melt-kneaded to carry out a transesterification reaction. There is a method of forming a pellet using a twin-screw extruder (hereinafter, this method is referred to as a “melt blending method”).

Further, a method of simply blending PET or a polyester mainly composed of PET and PAR at the time of melt molding (hereinafter, this method is referred to as "molding blending method").
However, in the present invention, it is more preferable to produce the polyester A by using both the melt blending method and the molding blending method.

The polyester B is usually obtained by subjecting a terephthalic acid component and an isophthalic acid component to esterification or transesterification, followed by melt polycondensation in the presence of a conventionally known catalyst. Also, PET
Or a polyester containing the same as a main component and polyethylene isophthalate (hereinafter referred to as “PEI”) or a polyester containing the same as a main component, usually a PEI-based polyester having a copolymerization amount of an isophthalic acid component of 80 mol% or more. Can be obtained in a required ratio.

The polyester C is usually obtained by using the polyester A and the polyester B at a predetermined ratio. PET or a polyester mainly composed of PET is obtained by a melt polycondensation reaction or a solid phase polymerization of a terephthalic acid component and an ethylene glycol component as main components, and has an intrinsic viscosity of 0.50 to 1 .20 are desirable.

In PET, in addition to the above components, phthalic acid,
Isophthalic acid, 2,5-dibromoterephthalic acid, 2,6
-Naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, aromatic dicarboxylic acid components such as diphenylsulfonedicarboxylic acid, trimellitic acid, trimesic acid,
Aromatic polycarboxylic acid component such as pyromellitic acid, aliphatic dicarboxylic acid component such as succinic acid, adipic acid, sebacic acid, azelaic acid, decanedicarboxylic acid, maleic acid, itaconic acid, diethylene glycol, triethylene glycol, propylene glycol Diol components such as 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, and polyethylene glycol; glycerin Polyhydric alcohol components such as trimethylolpropane and pentaerythritol, alicyclic diol components such as 1,4-cyclohexanedimethanol and 1,4-cyclohexanediethanol, p-xylylene glycol, bisphenol A and bis And aromatic diol component such as ethylene oxide adducts of phenol S may be a small amount copolymerized within a range not to impair the properties of PET.

The PAR in the present invention is an aromatic polyester obtained by polymerization of an aromatic dicarboxylic acid component and a bisphenol represented by the following formula, and preferably has an intrinsic viscosity of 0.40 to 1.00. .

HO—Ar ² —X—Ar ² —OH (wherein, Ar ² and X are the same as those in the formula.) Preferred examples of the aromatic dicarboxylic acid component include a terephthalic acid component and / or an isophthalic acid component. In particular, it is preferable to use a mixture of a terephthalic acid component and an isophthalic acid component in view of melt processability and overall performance of the obtained PAR. In the case of such a mixture, the mixing ratio can be arbitrarily selected, but a terephthalic acid component / isophthalic acid component is preferably from 9/1 to 1/9 (molar ratio),
In particular, in terms of balance between melt processability and performance, 7/3 to 3 /
7 (molar ratio), more preferably 1/1 (molar ratio).

The bisphenols represented by the formula include bisphenol A [2,2-bis (4-hydroxyphenyl) propane], 2,2-bis (4-hydroxy-
3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, bisphenol S [4 , 4'-dihydroxydiphenylsulfone], 4,4'-dihydroxydiphenylether, 4,4'-dihydroxydiphenylsulfide, 4,4'-dihydroxydiphenylketone, 4,4'-dihydroxydiphenylmethane,
1,1-bis (4-hydroxyphenyl) ethane, 1,
Examples thereof include 1-bis (4-hydroxyphenyl) cyclohexane, and bisphenol A is particularly preferable.
These may be used alone or in combination of two or more. Further, although the above bisphenols are para-forms, ortho- or meta-form bisphenols may be used, and ethylene glycol, propylene glycol or the like may be used in combination with these bisphenols.

As a preferred example of PAR, terephthalic acid chloride / isophthalic acid chloride = 1/1 (molar ratio)
And U-Polymer (trade name) manufactured by Unitika Ltd. obtained by interfacial polymerization of phenol and bisphenol A.

The PEI or the polyester mainly composed of the PEI according to the present invention is obtained by a melt polycondensation reaction or a solid phase polymerization of an isophthalic acid component and an ethylene glycol component as main components, and has an intrinsic viscosity. Is preferably in the range of 0.50 to 1.20.

PEI includes phthalic acid,
Terephthalic acid, 2,5-dibromoterephthalic acid, 2,6
-Naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, aromatic dicarboxylic acid components such as diphenylsulfonedicarboxylic acid, trimellitic acid, trimesic acid,
Aromatic polycarboxylic acid component such as pyromellitic acid, aliphatic dicarboxylic acid component such as succinic acid, adipic acid, sebacic acid, azelaic acid, decanedicarboxylic acid, maleic acid, itaconic acid, diethylene glycol, triethylene glycol, propylene glycol Diol components such as 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, and polyethylene glycol; glycerin Polyhydric alcohol components such as trimethylolpropane and pentaerythritol, alicyclic diol components such as 1,4-cyclohexanedimethanol and 1,4-cyclohexanediethanol, p-xylylene glycol, bisphenol A and bis And aromatic diol component such as ethylene oxide adducts of phenol S may be a small amount copolymerized within a range not to impair the properties of the PEI.

The toothbrush handle of the present invention uses a conventional P
It can be manufactured by directly applying the molding method used for ET-based polyester, and is obtained, for example, by injection-molding polyester A, polyester B, or polyester C into a mold using an injection molding machine. .

As described above, the handle for a toothbrush of the present invention is excellent in transparency, and does not have sink marks and whitening on a molded product.
Further, since it is excellent in flexibility and chemical resistance, it can be suitably used particularly as a handle for a medical toothbrush.

[0031]

Next, the present invention will be specifically described based on examples, but the present invention is not limited to only these examples. The measurement of various physical properties in the examples was carried out by the following methods.

(1) Intrinsic viscosity: Measured at a temperature of 20 ° C. using an equal weight mixture of phenol and ethane tetrachloride as a solvent, and expressed in units of dl / g.

(2) Appearance of test piece: A 127 × 12.7 × 3.2 mm test piece was injection molded using a polyester resin, and its transparency, whitening, generation of sink, etc. were visually observed. It was determined by the following two-stage evaluation method.

：: Excellent transparency, no whitening or sink marks occurred. X: Whitening or sink occurred.

(3) Flexibility: 127 × 12.7 × 3.2
A 100,000 bending test was performed using a mm test piece. In the bending test, as shown in FIG. 1, one end of the test piece 1 is fixed with a jig 2, and the other end of the test piece 1 is cycled with a cam 3 without applying the toothpaste powder 4 indicated by a virtual line. A bending displacement was applied, and the bending property was evaluated by the following two steps by the bending of the test piece 1 by the pressurization.

○: The test piece did not break even when the number of times of bending reached 100,000 times. X: The test piece broke before the number of bendings reached 100,000. The measurement conditions were an atmosphere of 23 ° C., a bending speed of 100 times / minute, and a strain rate of 0.8%.

The distortion rate r is determined by the following equation. r = (3dY) / (2L ² ) r: strain rate 0.08 d: thickness 3.2 mm Y: displacement 5.0 mm L: span 55 mm

(4) Chemical resistance: A toothpaste powder (manufactured by Lion Corporation, trade name: Clear Clean) 4 indicated by a virtual line is provided on the upper surface of the test piece 1 from the tip of the jig 2 to the contact position with the cam 3. The coating was uniformly applied so that the coating thickness became 5 mm, and the same bending test as above was performed 100,000 times. The evaluation method was evaluated in two stages of 上 記 as in the above.

Example 1 PET pellets with an intrinsic viscosity of 0.81 (manufactured by Unitika) and PAR powders with an intrinsic viscosity of 0.68 (manufactured by Unitika, U.S.A.)
And PET / PAR = 60/40 in weight ratio.
And the sodium acetate was added to the mixture at a charge ratio of 0.1%.
06 wt%, and twin screw extruder (PCM, manufactured by Ikegai Iron Works, Ltd.)
-30), melt-blended at 280 to 320 ° C., extruded into strands, and resin pellets (hereinafter, referred to as resin pellets).
This is referred to as “resin pellet A”. ) Was prepared.

Next, the resin pellet A was added with an intrinsic viscosity of 0.8
No. 1 PET pellet (produced by Unitika) was blended so that the ratio of / became / = 92 wt% / 8 wt%, and the cylinder temperature was 280 ° C. using an injection molding machine (produced by Toshiba Machine Co., Ltd., IS-100E). The above-mentioned test piece made of polyester A was produced under the conditions of a mold temperature of 40 ° C.

Table 1 shows the appearance, flexibility and chemical resistance of the obtained test pieces.

[0042]

[Table 1]

EXAMPLE 2 A 100-liter stainless steel reactor equipped with a stirrer, condenser and accumulator was prepared.
39.8 kg of terephthalic acid, 3.5 kg of isophthalic acid, and 16.2 kg of ethylene glycol, which are raw materials, were added so that the molar ratio of terephthalic acid to isophthalic acid was terephthalic acid / isophthalic acid = 92/8. did. Further, 9.5 g of triethyl phosphate was added as a heat stabilizer and stirred. The mixture is brought to a temperature of 210
After reacting at a temperature of 2.5 ° C. and a pressure of 2.5 kg / cm ² for 2.5 hours, the reaction was carried out at normal pressure for 2 hours, and water was continuously distilled off.

To the obtained reaction product, 26.6 g of antimony trioxide as a polycondensation catalyst and 9.5 g of triethyl phosphate as a heat stabilizer were added, the reaction temperature was raised to 260 ° C., and the reaction was carried out under a nitrogen atmosphere for 30 minutes. Maintained. Next, the nitrogen flow was stopped, and the pressure was reduced to 0.3 mmHg over 1 hour.
After maintaining the state for an additional 2.5 hours for reaction, the mixture was discharged in the form of a strand. After being cooled and solidified, it is cut into pellets, crystallized, and then cooled at 150 ° C. for 8 hours.
After drying under reduced pressure for a time, a resin pellet made of polyester B (hereinafter referred to as “resin pellet B”) was obtained. The ratio of / in the obtained resin pellet B is / = 92w
t% / 8 wt%.

Using an injection molding machine (manufactured by Toshiba Machine Co., Ltd., IS-100E), the pellets were heated to a cylinder temperature of 280.
The above-mentioned test piece was produced under the conditions of ° C and a mold temperature of 40 ° C.
Table 1 shows the appearance, flexibility and chemical resistance of the obtained test pieces.

Example 3 The resin pellets A produced in Example 1 and the resin pellets B produced in Example 2 differed in ratio of ///
= 85wt% / 8wt% / 7wt%, and injection molding machine (IS-100E, manufactured by Toshiba Machine Co., Ltd.)
The above-mentioned test piece made of polyester C was produced under the conditions of a cylinder temperature of 280 ° C. and a mold temperature of 40 ° C.

Table 1 shows the appearance, flexibility and chemical resistance of the obtained test pieces.

COMPARATIVE EXAMPLE 1 The ratio of / was made to be greater than the upper limit of the present invention by the ratio of / = 80 wt% / 20 wt%. Other than that, a test piece was produced in the same manner as in Example 1.

Table 1 shows the appearance, flexibility and chemical resistance of the obtained test pieces.

Comparative Example 2 The ratio of / was: / = 80 wt% / 20 wt%
Was made higher than the upper limit of the present invention. Otherwise, a test piece was prepared in the same manner as in Example 2.

Table 1 shows the appearance, flexibility and chemical resistance of the obtained test pieces.

Comparative Example 3 Using only an intrinsic viscosity of 0.81 PET (manufactured by Unitika) and an injection molding machine (manufactured by Toshiba Machine Co., Ltd., IS-100E) under the conditions of a cylinder temperature of 280 ° C. and a mold temperature of 15 ° C. Test pieces were prepared.

Table 1 shows the appearance, flexibility and chemical resistance of the obtained test pieces.

In Example 1, since the proportion of the structural unit represented by the above general formula was within the scope of the present invention, a polyester resin was used.
The transparency was good and no sink marks or whitening occurred.
In addition, even when the bending test was performed 100,000 times, no bending occurred and the flexibility was good. Furthermore, even if the bending test was carried out 100,000 times with the toothpaste powder, the powder did not deteriorate and was excellent in chemical resistance.

Example 2 uses a polyester resin in which the proportion of the structural unit represented by the general formula is within the scope of the present invention, and Example 3 uses the structural unit represented by the general formula. Since the ratio of the structural unit represented by and the structural unit represented by the polyester resin is within the scope of the present invention, good transparency as described above, without the occurrence of sink marks and whitening, flexibility and chemical resistance An excellent one was obtained.

In Comparative Example 1, since the ratio was too much higher than the upper limit of the present invention, when the bending test was performed 100,000 times with the toothpaste powder, breakage occurred 70,000 times. However, the chemical resistance was slightly inferior.

In Comparative Example 2, since the ratio was too much higher than the upper limit of the present invention, when the bending test was performed 100,000 times, the bending occurred 70,000 times, and when the toothpaste powder was applied, , Was broken after 50,000 times, resulting in inferior flexibility and chemical resistance.

In Comparative Example 3, since the test piece was made only of PET, whitening and sink occurred, resulting in a poor appearance of the test piece.

[0059]

According to the present invention, in the polyester A, polyester B, and polyester C forming the handle for the toothbrush, the structural unit represented by the above general formula is used as a main component in the above general formula, By blending at least one, there is no occurrence of whitening and sink marks,
A handle for a toothbrush excellent in transparency, chemical resistance, and flexibility can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an apparatus used for 100,000 bending tests.

[Explanation of symbols]

 Reference Signs List 1 test piece 2 jig 3 cam 4 toothpaste powder

Continued on the front page F-term (reference) 3B202 AA06 AB01 CA05 4J029 AA03 AB07 AC01 AD01 AE01 BA03 BB12A BB12B BB12C BB13A BB13B BD09A BD09B BE05A BF14A BF14B BG06X BG08X BH02 CB06J CB06B CG06

Claims (3)

[Claims] 1. A toothbrush handle made of a polyester resin, wherein the polyester resin is mainly composed of a structural unit represented by the following general formula and a structural unit represented by the following general formula. 9
A handle for a toothbrush, characterized in that it is blended in an amount of 5 to 85 wt% / 5 to 15 wt%. Embedded image 2. A toothbrush handle made of a polyester resin, wherein the polyester resin is mainly composed of a structural unit represented by the following general formula and a structural unit represented by the following general formula. 9
A handle for a toothbrush, characterized in that it is blended in an amount of 5 to 85 wt% / 5 to 15 wt%. Embedded image 3. A toothbrush handle made of a polyester resin, wherein the polyester resin has a structural unit represented by a structural unit represented by the following general formula and a structural unit represented by a main unit, and a total of 100 wt. % As 90% to 80% by weight / 5 to 15%
A toothbrush handle characterized in that it is blended so as to be 5% by weight / 5 to 15% by weight. Embedded image