JP2000108576A - Member for writing instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve adhesiveness with a skin and to suppress a slip at the time of writing, by blending a thermoplastic synthetic resin and at least a polymer having at least one repeating unit of a ring structure having at least three oxygen atoms with five carbons and one oxygen of a covalent bond by a single bond. SOLUTION: As a thermoplastic synthetic resin used as a base material of a molding for constituting each member of the writing instrument, a polypropylene, low density, high density and intermediate density polyethylenes, polystyrenes or the like are used with a low cost. A polymer having at least one repeating unit of a ring structure having at least three oxygen atoms so that five carbons and one oxygen of a covalent bond by a single bond is at least blended. As the polymer, starch, a glycogen, an inulin, a lichenin, a cellulose or the like is used. Particularly, by considering adhesiveness with the skin and an easiness of forming a composite material of metal, the structure is formed better as a main chain as compared with an introduction of the structure to a side chain. Its adding amount is preferably in the range of about 2 to 95%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a marking pen,
The present invention relates to a member made of a synthetic resin used for a writing implement such as a ballpoint pen and a mechanical pen, which is gripped by hand for writing, and a writing implement which stores ink inside and discharges ink from a pen tip.

[0002]

2. Description of the Related Art Conventionally, various synthetic resin materials have been used for writing instruments. However, irregularities or grooves are provided on a grip portion, rubber or elastomer is wrapped around the grip portion, or a paint having high frictional resistance is applied. Printing reduces the slipperiness when gripped. In addition, in places where sealing and fixing are required between components, such as a cap and a shaft, and a shaft and a tail plug, circumferential projections and recesses are provided or screwed. Further, in order to prevent the weight loss of the ink, polypropylene or polyethylene, which is a material which can relatively suppress the permeation of the ink solvent components such as water and alcohol, is used in a portion which is in direct contact with the ink.

[0003]

SUMMARY OF THE INVENTION In order to eliminate slipperiness, even if the grip portion has irregularities or grooves,
The material constituting the portion has almost no adsorptivity to the skin and is mainly made of a slippery synthetic resin from the beginning, and the fundamental slipperiness has not been eliminated. In addition, rubber, elastomer, etc., which are wound around the gripping part, because those having an inner diameter smaller than the outer diameter of the writing instrument are attached, the elasticity of the rubber, the elastomer itself requires time to attach to the writing instrument. . Further, printing a paint having high frictional resistance also complicates the work and increases the labor.

[0004] In the case of sealing or fixing between components by means of circumferential projections or recesses, the components are sealed and fixed, but intermolecular interactions between components such as van der Waals force and hydrogen bonding are performed. And electrostatic interactions are weak,
Since the adhesion between the parts is insufficient and a gap is easily formed at the interface between the parts, the possibility of ink transmission cannot be wiped out.

Further, since there is no affinity for hydroxyl groups of water, alcohol, etc., which are solvents of the ink, the ink is brought into contact with polypropylene or polyethylene, which is a material which transmits a very small amount between molecules of the member. Even when the ink is used for a member, the permeation of water, alcohol, or the like, which is a solvent of the ink, is not completely eliminated, so that the loss of ink over time cannot be avoided.

[0006]

That is, the present invention provides a thermoplastic synthetic resin as a base material, at least three or more oxygen atoms, and five carbon atoms and one oxygen are covalently bonded by a single bond. The gist of the present invention is a writing instrument member made of a synthetic resin material containing at least a polymer having at least one cyclic structure in a repeating unit.

[0007] The thermoplastic synthetic resin is used as a base material of a molded article constituting each member of the writing instrument. Specifically, polypropylene, low-density polyethylene, high-density polyethylene, medium-density polyethylene, polystyrene, Linear low density polyethylene, high molecular weight polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-acrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate Polymer, ethylene-methacrylic acid copolymer, polyvinyl alcohol, polymethyl methyl methacrylate, polyethylene oxide, ethylene vinyl alcohol, ethylene vinyl alcohol-carbon monooxide copolymer, ethylene butyl acrylate, acrylonitrile
Acrylic rubber-styrene copolymer, acrylonitrile-
Styrene copolymer, acrylonitrile-chlorinated polyethylene-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, polyvinyl chloride, chlorinated polyethylene, cellulose acetate resin, polytetrafluoroethylene resin, tetrafluoroethylene-6 Fluorinated propylene copolymer resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, tetrafluoroethylene-ethylene copolymer resin, polytrifluoroethylene chloride resin, polyvinylidene fluoride, polyoxymethylene homopolymer, polyoxy Methylene copolymer, nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, polyarylate resin, thermoplastic polyurethane elastomer, polyoxybenzoyl resin, polyetheretherketone resin,
Polysulfone resin, polyether sulfone resin, polyethylene terephthalate resin, polyethylene terephthalate copolymer, polybutylene terephthalate copolymer, polyethylene naphthalate, polybutylene naphthalate,
Examples thereof include polybutylene naphthalate copolymer, polycarbonate resin, polybutylene terephthalate resin, polyphenylene ether resin, polyphenylene sulfide resin, polybutadiene resin, and polymethylpentene.

In particular, considering that it is a low-priced product such as a writing instrument, it is a general-purpose resin such as polypropylene, low-density polyethylene, high-density polyethylene, medium-density polyethylene, polystyrene, acrylonitrile-styrene copolymer, acrylonitrile-butadiene. -Styrene copolymers, polyethylene terephthalate resins, polyethylene terephthalate copolymers and the like can be said to be suitable.

Examples of the polymer having at least three or more oxygen atoms and having at least one ring structure in which five carbon atoms and one oxygen atom are covalently bonded by a single bond in a repeating unit include starch, glycogen, and inulin. , Lichenin, cellulose, chitin, chitosan, hemicellulose, pectin, acacia, guar gum, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, methylcellulose, ethylcellulose, ethylhydroxyethylcellulose, carboxymethylethylcellulose and the like. The polymer may be modified or modified, and the modifying group may be, for example, an alkyl group for enhancing affinity with a resin, or an electron group for activating electron transition by ultraviolet / visible light for coloring. There are aromatic rings and the like.
Further, if the polymer is contained as a main component, paper containing cellulose as a main component, shells containing chitin as a main component, and the like can be used. Further, one kind of the above polymer may be used, or two or more kinds may be mixed.

In particular, considering the adhesion to the skin and the easiness of forming a complex with a metal, the compound has at least three or more oxygen atoms, and five carbon atoms and one oxygen atom are covalently bonded by a single bond. It can be said that those having a ring structure formed as a main chain are more preferable than those having a ring structure introduced into a side chain. The amount of addition is preferably 2-95% with respect to the synthetic resin, and if it is 2% or less, the frictional resistance may not be so high. If it is 95% or more, it is difficult to obtain the strength as a binding tool. There are cases.

The iron compound and the copper compound of the present invention are classified into a metal inorganic compound and a metal organic compound, and as the iron inorganic compound, iron (III) oxide, iron (II) oxide, iron bromide (II)
I), iron (II) chloride tetrahydrate, iron (II) chloride, iron (III) chloride, iron (III) chloride hexahydrate, reduced iron, iron, and copper inorganic compounds include bromide. Copper (I), copper (II) bromide, copper (I) chloride, copper (II) chloride, copper oxide (I), copper (II) oxide, reduced copper, copper, copper hydroxide (I
I), copper (II) sulfide, copper (II) chloride dihydrate, and copper (II) fluoride, and iron (I)
II) acetylacetonate, ammonium iron (III) citrate, iron (III) -acetylacetonate, ammonium iron (III) oxalate trihydrate, iron (III) citrate n hydrate, iron citrate ( III), iron (III) 4-cyclohexylacetate, iron (III) diphosphate,
Iron (III) 2-ethylhexylate, Iron fumarate (I
I), iron (II) lactate, iron (II) lactate trihydrate, iron naphthenate, iron (III) nitrate nonahydrate, iron (II) nitrate
I), iron (II) oxalate dihydrate, iron (II) oxide
I), ferric oxide, iron (2+) hexachloride hexahydrate, iron (III) perchlorate n hydrate, iron (III) phosphate n hydrate, iron (II) sulfate heptahydrate Hydrate, iron (III) sulfate n-hydrate, iron (III) hydroxide stearate, iron sulfide (I
I), triammonium iron oxalate (III), triammonium iron oxalate (III) trihydrate, iron ethylene tetraacetate, iron cacodylate, iron carbonyl powder, chloro (phthalocyaninato) iron (III) , Cyclopentadienyliron dicarbonyl iodide, iron (II) oxalate, ammonium sulfate (III) sulfate dodecahydrate, (tetracarboxyphthalocyaninato) iron (II), (tetra-t-butylphthalocyaninato) ) Iron (II), sodium pentacyanonitrosylferrate (III), hexacyanoiron (II)
I) potassium acid, potassium hexacyanoferrate (III) trihydrate, sodium ferrocyanide, sodium pentacyanoammineferrate (II) nhydrate, sodium pentacyanonitrosylferrate (III) dihydrate, Iron ammonium sulfate (III), iron ammonium sulfate (I
I), ammonium iron (II) sulfate hexahydrate and iron (II) sulfate heptahydrate, and copper organic compounds include copper (II) acetate, copper (II) sulfate, copper (II) acetate monohydrate Hydrate, ammonium copper (II) chloride dihydrate, copper (I) bromide-dimethylsulfide complex, basic copper (II) carbonate, copper (II) citrate, copper (II) citrate 2.5 water Japanese,
Copper (I) cyanide, Copper 4-cyclohexylacetate, Copper (II) diammonium chloride, Copper (I) ammonium chloride (I
I) dihydrate, copper (II) diphosphate tetrahydrate, copper (II) formate tetrahydrate, copper (II) oleate, copper (II) stearate, copper (II) chloride potassium Hydrate, potassium tetrachlorocuprate (II), copper oxine, copper (II) gluconate, sodium copper chlorophyllin, (chlorophthalocyaninato) copper (II), copper (II) oxalate
0.5 hydrate, copper (II) nitrate trihydrate, copper nitrate (I
I), (tetracarboxyphthalocyaninato) copper (I
I), potassium tetrachlorocuprate (II) dihydrate, copper (II) terephthalate trihydrate, copper (II) acetylacetonate, sodium copper chlorophyllin, phenylthio copper (I), copper phthalate (II) ), Copper (II) phthalocyanine, 1-butanethiol, copper (II) salts and copper (II) phosphate. Although a metal-inorganic compound or a metal-organic compound alone or a mixture can be used, considering the compatibility with a synthetic resin, it is preferable that both the iron compound and the copper compound are metal-organic compounds. The amount of the metal compound to be added is preferably 0.01 to 10% based on the synthetic resin.

A compound having a molecular weight of 1500 or less and having at least one carbonyl group in its structure is blended in order to make the dispersion of the complex in the synthetic resin uniform, and the fatty acid, fatty acid ester, Saturated fatty acids, unsaturated fatty acid esters, aromatic ketones, and the like, and examples of the fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, isostearic acid, and the like. Acid esters, palmitic acid esters, stearic acid esters, behenic acid esters, isostearic acid esters, and the like; unsaturated fatty acids include oleic acid and dimer acid; and unsaturated fatty acid esters include oleic acid esters and dimer acid esters. Benzophene as an aromatic ketone Emissions, anthraquinone, anthrone, acetyl benzophenone, there are 4-octyl benzophenone, even in one type or may be a mixture of two or more kinds. Further, as a mixture thereof, there are soybean oil, corn oil, olive oil, rapeseed oil, cottonseed oil, sunflower oil, peanut oil, linseed oil, and the like, and one kind or two or more kinds may be mixed. The amount of addition is preferably 0.1 to 20% with respect to the synthetic resin, and if it is 0.1% or less, it is difficult to be uniformly dispersed, and if it is 15% or more, the strength as a writing implement may not be maintained.

As a writing instrument using the present invention, there are a marking pen, a ball-point pen, a mechanical pen, and the like using a fiber converging body as a nib. In a writing instrument using ink, the ink is an aqueous ink using water as a solvent. Even if used, any oil-based ink containing an organic solvent as a main solvent and containing substantially no water may be used.

[0014]

The polymer compound such as starch mixed in a thermoplastic synthetic resin as a base material used for the writing instrument member of the present invention contains 5 carbon atoms and 1 oxygen atom in a repeating unit of the polymer. Individuals are covalently bonded only by a single bond to form a 6-membered ring structure. Since it has four hydroxyl groups in its ring, it easily forms hydrogen bonds with amide bonds in proteins, which is the main component of human skin, so it has good adhesion to skin and is easy to slip during writing. To prevent When a polymer in a synthetic resin constituting such a writing instrument is present together with a metal compound, a lone electron pair of a structural oxygen atom is attracted to the metal to form a complex.
In this composite, electrons are biased and an electrostatic interaction occurs between the writing implement components, so that the frictional resistance between the writing implement components is high and it is difficult to separate, and the adhesion between the components is improved. Further, by forming a complex, the amide bond and the hydrogen bond in the protein are further strengthened, and the slipperiness during writing is further suppressed. Further, the composite can easily capture water, alcohol, and the like that can pass through the synthetic resin into the structure thereof, suppress the permeation of water and alcohol, and prevent ink loss. Further, the carbonyl group is electrostatically bonded to the complex of the polymer and the metal by an electrostatic interaction, and the complex is synthesized due to the high affinity of the linear portion composed of four or more carbon atoms with the synthetic resin portion. It is uniformly dispersed in the resin.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 shows a marking pen A using a water-based ink and a converging body of polyester fiber as a pen tip. An ink occluding body 1 made of a converging body of a polypropylene fiber impregnated with the water-based ink has a shaft 2. A pen tip 3 is pierced into the ink storage body 1 via a holder 4, a tail plug 5 is fixed to the rear end of the shaft 2, and a cap 6 is detachably mounted at the front end. By being attached, the inside of the pen point 3 and the shaft 2 is kept airtight. When writing, the cap 6 is removed and writing is performed by abutting the pen tip 3 on the writing surface. When the ink of the pen tip 3 becomes low, the ink impregnated in the ink occluding body 1 is applied to the pen tip 3. Moving. Further, an air hole 7 is formed at a position covered by the cap 6 which is a front portion of the shaft 2, and air is taken into the shaft 2 to replace the ink with ink as ink is consumed at the time of writing. This enables smooth movement of the ink from the ink storage 1 to the pen tip 3.

As shown in FIG. 2 which is an enlarged view of a portion I in FIG. 1, the cap 6 has a press-fitting portion 6a for fixing to the shaft 2.
An annular inward projection 6b is formed to seal the space inside the cap that covers the pen tip 3 and the air hole 7, and is pressed against the shaft 2 when the illustrated cap is mounted.

As shown in FIG. 3 which is an enlarged view of the portion II in FIG. 1, the tail plug 5 is formed with an annular inward projection 5a for sealing the space inside the shaft. Also serves as a press-fitting part for fixing. In the illustrated state with the tail plug attached, it is pressed against the shaft 2.

Regarding the above-described marking pen,
Examples of marking pens in which each member was made of various materials and combinations thereof were made. Material Example 1 9 kg of Nisseki Polypro J160F polypropylene (manufactured by Nippon Petrochemical) and 1 kg of starch and corn (manufactured by Wako Pure Chemical Industries, Ltd.)
A mixture.

Material Example 2 9 kg of Nisseki Polypro J160F polypropylene (manufactured by Nippon Petrochemical Co., Ltd.) is mixed with 1 kg of cellulose cellulose and microcrystals (manufactured by Wako Pure Chemical Industries, Ltd.).

Material Example 3 To 9 kg of Nisseki Polypro J160F polypropylene (manufactured by Nippon Petrochemical Co., Ltd.), 0.5% starch and maize (manufactured by Wako Pure Chemical Industries, Ltd.) were added.
and 0.5 kg of cellulose, cellulose as cellulose, and microcrystals (manufactured by Wako Pure Chemical Industries, Ltd.).

Material Example 4 To 10 kg of the mixture of Material Example 1, 0.25 k of iron (III) oxide (manufactured by Wako Pure Chemical Industries, Ltd.) as an inorganic metal compound was added.
g, and 0.25 kg of copper (II) oxide (manufactured by Wako Pure Chemical Industries, Ltd.) as an inorganic metal compound.

Material Example 5 Iron (III) oxide (manufactured by Wako Pure Chemical Industries, Ltd.), which is an inorganic metal compound, was added in an amount of 0.25 k to 10 kg of the mixture of Material Example 1.
g and 0.25 kg of organometallic compound copper (II) oleate (manufactured by Wako Pure Chemical Industries, Ltd.).

Material Example 6 To 10 kg of the mixture of Material Example 1, 0.25 kg of an organic metal compound, ammonium iron (III) citrate, brown (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.25 kg of an oxidized inorganic metal compound 0.25 kg of copper (II) (manufactured by Wako Pure Chemical Industries, Ltd.)
A mixture of

Material Example 7 To 10 kg of the mixture of Material Example 1, 0.25 kg of an organic metal compound, iron (III) ammonium citrate, brown (manufactured by Wako Pure Chemical Industries, Ltd.), and olein, an organic metal compound, were added. Copper (II) acid (manufactured by Wako Pure Chemical Industries, Ltd.)
A mixture of 5 kg.

Material Example 8 0.5 kg of oleic acid (manufactured by Wako Pure Chemical Industries, Ltd.), which is an unsaturated fatty acid, is mixed with 11 kg of the mixture of Material Example 7.

Material Example 9 Ethyl oleate (manufactured by Wako Pure Chemical Industries, Ltd.), which is an unsaturated fatty acid ester, was added to 11 kg of the mixture of Material Example 7 in 0.1 kg.
A mixture of 5 kg.

Material Example 10 A mixture of 11 kg of the mixture of Material Example 7 and 0.5 kg of olive oil (manufactured by Wako Pure Chemical Industries, Ltd.), which is a mixture of unsaturated fatty acids and unsaturated fatty acid esters.

Material Example 11 To 11 kg of the mixture of Material Example 7, 0.49 kg of olive oil (manufactured by Wako Pure Chemical Industries, Ltd.), which is a mixture of unsaturated fatty acid and unsaturated fatty acid ester, and benzophenone (aromatic ketone) were added. A mixture of 0.01 kg of Kojun Pharmaceutical Co., Ltd.).

Example 1 The shaft, tail plug, cap, and holder of the marking pen shown in FIG. 1 were injection-molded with the material described in Material Example 1, and a polyester fiber converging body was used for the pen tip. The sample of Example 1 was obtained by using a polypropylene fiber bundle impregnated with an aqueous ink for the occlusion body.

Example 2 The shaft, tail plug, cap, and holder of the marking pen shown in FIG. 1 were injection-molded with the material described in Material Example 2, and a polyester fiber converging body was used for the pen tip to form an ink. The sample of Example 2 was obtained by using a polypropylene fiber bundle impregnated with the aqueous ink for the occlusion body.

Example 3 The shaft, tail plug, cap, and holder of the marking pen shown in FIG. 1 were injection-molded with the material described in Material Example 3, and a polyester fiber converging body was used for the pen tip to form an ink. A sample of Example 3 was obtained by using a polypropylene fiber bundle impregnated with an aqueous ink for the occlusion body.

Example 4 The shaft, tail plug, cap, and holder of the marking pen shown in FIG. 1 were injection-molded with the material described in Material Example 4, and a polyester fiber converging body was used for the pen tip. A sample of Example 4 was obtained by using a polypropylene fiber bundle impregnated with an aqueous ink for the occlusion body.

Example 5 An outer shaft, a tail plug, a cap, and the like of the marking pen shown in FIG.
By injection molding the holder portion with the material described in Material Example 5, and using a polyester fiber converging body for the pen tip,
A sample of Example 5 was obtained by using a polypropylene fiber bundle impregnated with an aqueous ink in the ink occluding body.

Example 6 An outer shaft, a tail plug, a cap, and the like of the marking pen shown in FIG.
By injection-molding the holder portion with the material described in Material Example 6, and using a polyester fiber converging body for the pen tip,
A sample of Example 6 was obtained by using a polypropylene fiber bundle impregnated with an aqueous ink for the ink occluding body.

Example 7 An outer shaft, a tail plug, a cap, and the like of the marking pen shown in FIG.
By injection molding the holder part with the material described in Material Example 7, and using a polyester fiber converging body for the pen tip,
A sample of Example 7 was obtained by using a polypropylene fiber bundle impregnated with an aqueous ink in the ink occluding body.

Example 8 An outer shaft, a tail plug, a cap, and the like of the marking pen shown in FIG.
By injection molding the holder portion with the material described in Material Example 8, and using a polyester fiber converging body for the pen tip,
The sample of Example 8 was obtained by using a polypropylene fiber bundle impregnated with the aqueous ink in the ink occluding body.

Example 9 An outer shaft, a tail plug, a cap, and the like of the marking pen shown in FIG.
By injection molding the holder portion with the material described in Material Example 9, and using a polyester fiber converging body for the pen tip,
A sample of Example 9 was obtained by using a polypropylene fiber bundle impregnated with an aqueous ink for the ink occluding body.

Example 10 An outer shaft, a tail plug, a cap, and the like of the marking pen shown in FIG.
The sample of Example 10 was obtained by injection-molding the holder portion with the material described in Material Example 10, and by using a polyester fiber converging body for the pen tip and a polypropylene fiber bundle impregnated with aqueous ink in the ink occluding body. I got

Example 11 An outer shaft, a tail plug, a cap, and the like of the marking pen shown in FIG.
The sample of Example 11 was obtained by injection-molding the holder portion with the material described in Material Example 11, and by using a polyester fiber bundle for the pen tip and a polypropylene fiber bundle impregnated with aqueous ink in the ink occluding body. I got

Comparative Example 1 An outer shaft, a tail plug, a cap, and the like of the marking pen shown in FIG.
Nisseki Polypro J1 whose holder is polypropylene
By injection molding with 60F (manufactured by Nippon Petrochemical Co., Ltd.), and using a polyester fiber converging body at the pen tip,
A sample of Comparative Example 1 was obtained by using a polypropylene fiber bundle impregnated with an aqueous ink in the ink occluding body.

Sliding load test Under the environment of a temperature of 20 ° C. and a humidity of 50%, the grip portion of each sample is held between the thumb and the index finger with a force of 200 g.
The load at which the sample, which was pressed vertically with the pen tip against the platform scale and held between the thumb and the index finger, began to slide, was defined as the sliding load of the sample. Table 1 shows the results.

Ink Weight Loss Test After leaving each sample for one month in an environment of a temperature of 50 ° C. and a humidity of 30%, the weight was measured and the value of the weight loss was taken as the ink weight loss value. Table 1 shows the results. Table 1 shows the results of each test.

[0043]

[Table 1]

[0044]

The writing instrument of the present invention has good adhesion to the skin, suppresses slippage during writing, and has high adhesion between parts, so that the amount of ink loss is as small as possible.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment.

FIG. 2 is an enlarged view of a portion I in FIG.

FIG. 3 is an enlarged view of a portion II in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink occlusion body 2 shaft 3 Pen tip 4 Holder 5 Tail plug 5a Inward projection 6 Cap 6a Press-fit part 6b Inward projection 7 Air hole

Claims (5)

[Claims] 1. A repeating unit comprising a thermoplastic synthetic resin as a base material and a ring structure having at least three or more oxygen atoms, wherein five carbon atoms and one oxygen atom are covalently bonded by a single bond. A writing instrument member made of a synthetic resin material containing at least the above-mentioned polymer. 2. The writing instrument member according to claim 1, wherein the polymer is a polysaccharide. 3. The writing instrument member according to claim 1, wherein an iron and / or copper compound is mixed in the synthetic resin material. 4. The member for a writing instrument according to claim 3, wherein the iron and / or copper compound is an organic compound. 5. The writing instrument member according to claim 3, wherein a compound having at least one carbonyl group in its structure and a molecular weight of 1500 or less is mixed in the synthetic resin material.