JP2000001611A - Nail made of synthetic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nail made of synthetic resin having a high rigidity, hardly causing the decrease of a flexural modules even if the resin absorbing water, and capable of being cheaply produced. SOLUTION: This nail is composed of a synthetic resin, and the synthetic resin comprises 30-50 wt.% polyamide resin obtained by compounding a crystalline polyamide resin and an amorphous polyamide resin in a weight ratio of the crystalline polyamide to the amorphous polyamide regulated so as to be (90/10)-(10/90), and 70-50 wt.% glass fiber with the proviso that the total percentage of the polyamide resin and the glass fiber is regulated so as to be 100 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin nail, and more particularly, to a nail having a high bending rigidity required for withstanding a large bending force applied when nailing, and a small decrease in bending rigidity even when water is absorbed. In addition, the present invention relates to a synthetic resin nail having good workability such as nailing and nail cutting.

[0002]

2. Description of the Related Art Conventionally, metal nails having excellent strength have been widely used as nails used for joining wood pieces. However, metal nails have a problem that they are easily rusted, and when used for woodworking, there is also a problem that they cannot be hooked on the nailed surface. In addition, if an attempt is made to apply paint to the surface of a nail made of metal, it is difficult to apply paint to the head of the nail, and the appearance tends to be poor. In addition, there are many fields that are not suitable for actual use because they are inferior in heat insulation when made of metal.

In recent years, nailing using an automatic nailing machine has been proposed in order to improve workability. This automatic nailing machine performs a nailing operation at a high speed, for example, by filling a continuous binding type nail in which the heads of the nails are connected via a connecting portion. In such a continuous nail, it is necessary to cut off the connecting portion at the time of nailing and to strike out as an individual nail. However, with a metal nail, the connecting portion is hard and cannot be easily separated, resulting in poor workability. There was a problem of inferiority.

As a solution to such a problem, a resin nail made of a synthetic resin has been proposed. As the synthetic resin used for the resin nail, for example, a polyamide resin, a polycarbonate resin, a polybutylene terephthalate resin, or the like, which has excellent mechanical strength such as tensile strength, bending strength, and impact strength is used. However, if a nail is made only of such a synthetic resin, the instantaneous impact applied when nailing is not sufficient, and the strength enough to withstand a large bending force is not sufficient. It is common to improve flexural rigidity and impact strength by blending.

However, a nail made of such a resin composition has a problem that the bending rigidity is reduced when moisture is absorbed. Therefore, the field of use is limited, and the reliability is low for long-term use. There was a problem.

To solve such a problem, Japanese Patent No. 2705817 discloses a resin composition formed of a polyamide resin having an equilibrium moisture absorption of 5% or less, glass fiber, and a thermo-liquid crystal resin. Disclosed are synthetic resin nails.

This synthetic resin nail has a small decrease in bending elastic modulus and Izod impact strength even when water is absorbed, but its bending elastic modulus itself is about 12 GPa, and it also has sufficient bending rigidity. Was not. further,
Since it is necessary to mix expensive thermo-liquid crystal resin into the resin composition constituting the nail, there is a problem that the cost is high, and a nail made of a synthetic resin that can be manufactured at low cost has been desired.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above problems and provides a synthetic resin nail which has a high bending rigidity, has a small decrease in bending rigidity even when water is absorbed, and can be manufactured at low cost. It is.

[0009]

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 relates to a nail made of a synthetic resin, wherein the synthetic resin is composed of a crystalline polyamide resin and an amorphous polyamide resin in a weight ratio of (crystalline polyamide resin) / (amorphous polyamide resin) = 90. / 10 to 10 /
A total of 10 to 50% by weight of polyamide resin 30 to 50% by weight and 70 to 50% by weight of glass fiber blended to be 90
The present invention provides a synthetic resin nail characterized in that the nail consists of 0% by weight.

According to the present invention, the polyamide resin comprises a crystalline polyamide resin and an amorphous polyamide resin,
By filling the glass fiber as high as 70 to 50% by weight, the orientation of the glass fiber can be in the length direction of the nail and can be evenly distributed. can do. In addition, since the amorphous polyamide resin is blended in the polyamide resin at a specific ratio, even if water is absorbed, the subsequent decrease in bending rigidity is small. In addition, when molded as a continuous nail, it is used in automatic nailing machines because the pillars of the nail have high bending rigidity and the connecting part that connects the heads of the nails is made of resin and can be easily separated. It can also be suitably used as a continuous spelling type nail. Further, since the nail made of synthetic resin is composed only of polyamide resin and glass fiber, it can be made inexpensive.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The synthetic resin constituting the synthetic resin nail of the present invention is a crystalline polyamide resin and an amorphous polyamide resin in a weight ratio of (crystalline polyamide resin) / (amorphous polyamide resin). ) = 90/10 to 10/90, and must be composed of a polyamide resin and glass fiber that functions as a reinforcing material.

Crystalline polyamide resin is a resin having excellent mechanical properties. By highly filling glass fiber, the glass fiber can be oriented in the length direction of the nail, and therefore has high bending rigidity. It can be a resin nail. Furthermore, by blending the amorphous polyamide resin in the polyamide resin at a specific ratio, a decrease in bending rigidity after absorbing water can be suppressed.

The mixing ratio of the crystalline polyamide resin and the amorphous polyamide resin is (weight ratio: (crystalline polyamide resin) / (amorphous polyamide resin)) = 90/10 to 10 /
Must be 90. The amorphous polyamide resin is intended to prevent a decrease in flexural rigidity after water absorption, and when the amount is less than the lower limit of the blending ratio, the effect of preventing a decrease in flexural rigidity after water absorption is not obtained. If it exceeds, the amorphous polyamide resin has low crystallinity, so that a molding cycle in injection molding or the like is extended and productivity is deteriorated.

The mixing ratio of the polyamide resin and the glass fiber constituted as described above is 30 to 50 of the polyamide resin.
% Of glass fiber and 70 to 50% by weight of glass fiber.
It must be 00% by weight. If the compounding ratio of the polyamide resin is less than 30% by weight, the moldability will decrease, and if the compounding ratio of the polyamide resin exceeds 50% by weight, the bending rigidity will decrease.

Further, as described above, the nail made of synthetic resin of the present invention can be made inexpensive because it is composed only of polyamide resin and glass fiber. The crystalline polyamide resin constituting the polyamide resin is obtained by polymerizing or polycondensing an aminocarboxylic acid, a lactam or a diamine with a dicarboxylic acid (including a pair of salts thereof). 6), polytetramethylene adipamide (nylon 4
6), polyhexamethylene adipamide (nylon 6
6), polyhexamethylene sebacamide (nylon 61
0), polyhexamethylene dodecamide (nylon 61
2) Polyundecamethylene adipamide (nylon 11
6), polyundecamide (nylon 11), polydodecamide (nylon 12), polytrimethylhexamethylene terephthalamide (nylon TMHT), polyhexamethylene isophthalamide (nylon 6I), polyhexamethylene terephthal / isophthalamide (nylon 6T)
/ 6I), polybis (4-aminocyclohexyl) methandodecamide (Nylon PACM12), polybis (3
-Methyl-4-aminocyclohexyl) methanedodecamide (nylon dimethyl PACM12), polymethaxylylene adipamide (nylon MXD6), polyundecamethylene terephthalamide (nylon 11T), polyundecamethylene hexahydroterephthalamide (nylon 11T (H)), polyhexamethylene adipamide / terephthalamide (nylon 66 / 6T), polyhexamethylene adipamide / terephthalamide / isophthalamide (nylon 66 / 6T / 6I), polyhexamethylene /
Examples include 3-methylhexamethylene terephthalamide (nylon 6DT), polycaproamide hexamethylene terephthalamide (nylon 66T), polynonamethylene terephthalamide (nylon 9T), and copolymerized polyamides and mixed polyamides thereof. Among them, nylon 6, nylon 46, nylon 66, nylon 11, nylon 12, and their copolymerized polyamides and mixed polyamides can be suitably used, and nylon 6, nylon 66 and their mixed polyamides can be particularly preferably used.

The polyamide resin can be used not only alone but also as a reinforced polyamide resin in which a layered silicate is uniformly dispersed at a molecular level. In the reinforced polyamide resin, it is preferable that 0.1 to 10% by weight of the layered silicate is uniformly dispersed at the molecular level. If the compounding ratio of the layered silicate is less than 0.1% by weight, the bending strength and the bending strength are reduced. It is inferior in mechanical strength such as elastic modulus and heat resistance. On the other hand, if the content of the layered silicate is more than 10% by weight, injection molding into nails becomes difficult.

The phrase "layered silicate is uniformly dispersed in a polyamide resin at a molecular level" means a state where each layered silicate has an average interlayer distance of 20 ° or more when dispersed in a polyamide resin matrix. Here, the interlayer distance refers to the distance between the centers of gravity of the layered silicates, and the term “uniformly dispersed” means that one of the silicate layers or a multilayer having an average overlap of 5 or less is formed in parallel. Or, in a state where random, or a mixture of parallel and random,
A state in which 0% or more, preferably 70% or more is dispersed without forming a lump. For example, when the swellable fluoromica-based mineral as a layered silicate is uniformly dispersed at the molecular level, when a wide-angle X-ray diffraction measurement is performed on the resin pellet, 1
The peak at 2 to 13 ° disappears. Therefore, the dispersion state of the swellable fluoromica-based mineral can be confirmed by this measurement.

Since the layered silicate is uniformly dispersed at the molecular level in the polyamide resin as described above, the nail is excellent in rigidity such as bending strength and flexural modulus, heat resistance and impact resistance, and is lightweight. It becomes a reinforced polyamide resin that can be used.

Examples of the layered silicate compounded in the reinforced polyamide resin include smectite minerals such as montmorillonite, beidellite, saponite, hectorite, and sauconite; vermiculite minerals such as vermiculite;
Mica-based minerals such as muscovite, biotite, paragonite, levitrite, swellable fluoromica, brittle mica-based minerals such as margarite, clintonite, and anandite, dombasite;
Chlorite-based minerals such as sudoite, cocoaite, clinochlore, chamosite, and nimite, and hydrous inosilicate-based minerals such as sepiolite, etc. Swellable fluoromica-based minerals that do not particularly require pretreatment with a salt can be suitably used.

Although the relative viscosity of the crystalline polyamide resin is not particularly limited, the relative viscosity is determined by using a 96% by weight concentrated sulfuric acid as a solvent at a temperature of 25 ° C. and a concentration of 1 g / dl. Those in the range of 5 to 5.0 are preferred. When the relative viscosity is less than 1.5, the mechanical strength such as the bending strength and the bending elastic modulus of a nail is reduced. On the other hand, when the relative viscosity exceeds 5.0,
It is not preferable because the moldability rapidly decreases.

Examples of the amorphous polyamide resin include polyamide resins having a heat of fusion of 1 cal / g or less when measured at a heating rate of 16 ° C. in a nitrogen atmosphere using a differential scanning calorimeter. Polycondensate of acid / terephthalic acid / hexamethylenediamine, polycondensate of isophthalic acid / terephthalic acid / hexamethylenediamine / bis (3-methyl-4-aminocyclohexyl) methane, isophthalic acid / 2,2,4-trimethyl Polycondensate of hexamethylenediamine / 2,4,4-trimethylhexamethylenediamine, polycondensate of terephthalic acid / 2,2,4-trimethylhexamethylenediamine / 2,4,4-trimethylhexamethylenediamine, isophthalic acid / Terephthalic acid / 2,2,4-trimethylhexamethylenediamine / 2,4,4-to Polycondensate of methylhexamethylenediamine, isophthalic acid / bis (3-methyl-4-aminocyclohexyl) methane / ω-laurolactam polycondensate, terephthalic acid / bis (3-methyl-4-aminocyclohexyl) methane / and polycondensates of ω-laurolactam. In addition, those in which the benzene ring of the terephthalic acid component and / or the isophthalic acid component constituting these polycondensates is substituted with an alkyl group or a halogen atom are also included. Further, two or more of these amorphous polyamides may be used in combination.

The glass fiber used in the present invention is used for reinforcing the above polyamide resin. The amount of the glass fiber used is 70 to 5% based on 30 to 50% by weight of the polyamide resin.
0% by weight. Further, the diameter and length of the glass fiber is not particularly limited, but if the fiber length is too long, it is difficult to uniformly mix and disperse with the polyamide resin, and if the fiber length is too short, as a reinforcing material. In general, the fiber length is preferably from 0.1 to 10 mm, particularly preferably from 0.1 to 7 mm, and more preferably from 0.3 to 4 mm, because the effect of the above becomes insufficient. Also,
The glass fiber preferably has a diameter in the range of 9 to 13 μm. As such a glass fiber, a fiber treated with a surface treatment agent as needed for the purpose of improving the interfacial adhesion to the polyamide resin to enhance the reinforcing effect may be used.

The above synthetic resin has a light stabilizer, a plasticizer, a lubricant, and a light stabilizer as long as its properties are not significantly impaired.
Dyes, release agents, pigments, flame retardants, and the like may be added, and these are added when the resin composition is melt-kneaded or melt-molded.

The nail made of a synthetic resin as described above is molded by an injection molding method, and its mold may be either a cold runner system or a hot runner system. Further, the shape of the nail is not particularly limited, but may be a known shape such as a cylindrical portion, an elliptical shape, or a prismatic shape. Each of these nails may be formed individually, or several to several tens of nails may be used as continuous staking nails used in an automatic nailing machine or the like. Part of the portion may have a shape connected via a connecting portion. When molded as a continuous nail, the nail has a high bending rigidity and the connecting part is made of resin, so it is easy to separate, so it is also suitable as a continuous nail used in automatic nailing machines. And workability can be improved.

[0025]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In addition, the measurement of various physical property values in the following Examples and Comparative Examples was performed by the following methods.

(1) Flexural modulus (GPa): thickness 3.2
A test piece having a width of 12.7 mm, a width of 12.7 mm and a length of 127 mm was prepared, and the flexural modulus was measured according to the method described in ASTM-D790. The flexural modulus of the test piece after immersion in water at 23 ° C. for 7 days was measured in the same manner.

(2) Izod impact strength (J / m): A
Notched, according to the method described in STM-D256,
Izod impact strength was measured on a test piece having a thickness of 1/2 inch under a stress of 1.86 MPa. In addition, the Izod impact strength of the test piece after immersion in water at 23 ° C. and elapse of 7 days was similarly measured.

(3) Water absorption (%): A test piece having a thickness of 3.2 mm, a width of 12.7 mm, and a length of 127 mm was prepared.
The sample was immersed in water at ℃ and the water absorption was measured from the weight change after 7 days.

(4) Nail driving test: total length 38 mm, head length 1 mm, column length 35 mm, tip 2 m
m, 10 nails with a hexagonal cross section were created, and 23
It was immersed in water at ℃ for 7 days. Then, after 7 days, the nail is taken out, and the thickness is 10 mm, the width is 40 mm, and the length is 40.
It was hammered into the mm cedar timber. And
We examined how many of the 10 were broken or missing.

Example 1 In order to measure the above physical properties, first, a synthetic resin pellet was prepared. As a resin component, 32% by weight of nylon 66 (manufactured by DuPont, Zytel 101) having a relative viscosity of 2.7 as a crystalline polyamide and isophthalic acid / terephthalic acid / hexamethylenediamine / bis (3- 8% by weight of a polycondensate of methyl-4-aminocyclohexyl) methane (CX3000, manufactured by Unitika). 60 wt% of glass fiber (manufactured by Nippon Electric Glass Co., Ltd., T-259) was combined with 40 wt% of this resin component and melt-kneaded using a twin screw extruder (TEH37BS, manufactured by Toshiba Machine Co., Ltd.) to produce resin pellets. . The cylinder temperature was 290 ° C.

Then, an injection molding machine (made by Toshiba Machine Co., Ltd., IS-
According to 100E), the resin pellets were melt-kneaded at a cylinder temperature of 280 ° C., and the test piece and the nail were injection-molded at a mold temperature of 120 ° C.

The flexural modulus, Izod impact strength, and water absorption before and after water absorption were measured in accordance with the above measurement method, and a nailing test after water absorption was performed. Table 1 shows the obtained measurement results.

[0033]

[Table 1]

Example 2 A polycondensate of isophthalic acid / terephthalic acid / hexamethylenediamine (manufactured by EMS, G
-21) was used. Table 1 shows the mixing ratio of the crystalline polyamide resin and the amorphous polyamide resin. The cylinder temperature was 280 ° C.

Otherwise, in the same manner as in Example 1,
Test pieces and resin nails were prepared. Table 1 shows the measurement results of the bending elastic modulus, Izod impact strength, and water absorption of the obtained test piece before and after water absorption, and the result of the nailing test.

Example 3 Nylon 6 having a relative viscosity of 2.5 (A1030BRL, manufactured by Unitika Ltd.) was used as a crystalline polyamide resin. Further, the compounding ratio of the crystalline polyamide resin and the amorphous polyamide resin was as shown in Table 1, and the compounding ratio of the glass fiber was more than that of Example 1 and was 70% by weight. The cylinder temperature was 280 ° C.

Otherwise, in the same manner as in Example 1,
Test pieces and resin nails were prepared. Table 1 shows the measurement results of the bending elastic modulus, Izod impact strength, and water absorption of the obtained test piece before and after water absorption, and the result of the nailing test.

Example 4 Nylon 66 of Example 1 (Zytel 101 manufactured by DuPont) and nylon 6 of Example 3 as crystalline polyamides
(A1030BRL, manufactured by Unitika Ltd.). Further, the mixing ratio of the crystalline polyamide resin and the amorphous polyamide resin is shown in Table 1, and the cylinder temperature was set at 28.
0 ° C.

Otherwise, the same as in Example 1,
Test pieces and resin nails were prepared. Table 1 shows the measurement results of the bending elastic modulus, Izod impact strength, and water absorption of the obtained test piece before and after water absorption, and the result of the nailing test.

Example 5 Nanocrystalline nylon 6 having a relative viscosity of 2.3 (M1030D, manufactured by Unitika) was used as a crystalline polyamide resin.
Was used. This nanocomposite nylon 6 contained 4% by weight of a swellable fluoromica mineral in the resin. Further, the compounding ratio of the crystalline polyamide resin and the amorphous polyamide resin was as shown in Table 1, and the compounding ratio of the glass fiber was smaller than that of Example 1 and was 50% by weight. The cylinder temperature was 280 ° C.

Other than that, the same as in Example 1,
Test pieces and resin nails were prepared. Table 1 shows the measurement results of the bending elastic modulus, Izod impact strength, and water absorption of the obtained test piece before and after water absorption, and the result of the nailing test.

Example 6 Table 1 shows the mixing ratio of the crystalline polyamide resin and the amorphous polyamide resin.

Other than that, the same as in Example 1,
Test pieces and resin nails were prepared. Table 1 shows the measurement results of the bending elastic modulus, Izod impact strength, and water absorption of the obtained test piece before and after water absorption, and the result of the nailing test.

Example 7 Nylon 6 having a relative viscosity of 2.5 (manufactured by Unitika Ltd.), which is the crystalline polyamide resin of Example 3, was used as the polyamide resin.
A1030BRL) 12% by weight and the amorphous polyamide of Example 2 (G-21, manufactured by EMS Co., Ltd.) 28% by weight were used. The cylinder temperature was 280 ° C.

Otherwise, the same as in Example 1,
Test pieces and resin nails were prepared. Table 1 shows the measurement results of the bending elastic modulus, Izod impact strength, and water absorption of the obtained test piece before and after water absorption, and the result of the nailing test.

In all of Examples 1 to 7, since the crystalline polyamide resin, the amorphous polyamide resin, and the glass fiber were blended within the range of the present invention, the flexural modulus and the Izod impact strength were high. Further, even after water absorption, the bending elastic modulus did not decrease much, so that a good nailing test result was obtained.

Comparative Example 1 The nylon 6 of Example 1 was used as the crystalline polyamide resin without using the amorphous polyamide resin as the polyamide resin.
6 (manufactured by DuPont, Zytel 101) alone. The mixing ratio of the polyamide resin and the glass fiber was as shown in Table 1.

Otherwise, the same as in Example 1,
Test pieces and resin nails were prepared. Table 1 shows the measurement results of the bending elastic modulus, Izod impact strength, and water absorption of the obtained test piece before and after water absorption, and the result of the nailing test.

Comparative Example 2 The same procedure as in Example 5 was repeated except that the amorphous polyamide resin was not used.
(A1030BRL, manufactured by Unitika) alone.

Otherwise, in the same manner as in Example 1,
Test pieces and resin nails were prepared. Table 1 shows the measurement results of the bending elastic modulus, Izod impact strength, and water absorption of the obtained test piece before and after water absorption, and the result of the nailing test.

Comparative Example 3 The nylon 6 of Example 5 was used as the crystalline polyamide resin without using the amorphous polyamide resin as the polyamide resin.
(M1030D, manufactured by Unitika) alone. Also,
The mixing ratio of the polyamide resin and the glass fiber was as shown in Table 1.

Otherwise, the same as in Example 1,
Test pieces and resin nails were prepared. Table 1 shows the measurement results of the bending elastic modulus, Izod impact strength, and water absorption of the obtained test piece before and after water absorption, and the result of the nailing test.

In each of Comparative Examples 1 to 3, since no amorphous polyamide resin was blended, the water absorption increased, and the decrease in the flexural modulus after water absorption increased. Therefore, even in a nailing test after water absorption, breakage or chipping occurred in about half of the nails, and good results could not be obtained.

[0054]

According to the present invention, the polyamide resin 30 to 30
By blending 70 to 50% by weight of glass fiber with 50% by weight, sufficient bending rigidity for use as a nail can be obtained.
In addition, as the polyamide resin, not only the crystalline polyamide resin but also an amorphous polyamide resin is compounded, and the compounding ratio is (weight ratio: (crystalline polyamide resin) / (amorphous polyamide resin)) = 90/10 to 10 / By setting it to 90, a decrease in bending stiffness after water absorption is reduced, workability such as nailing property and nail pulling property is good, and a nail with good nail pulling property can be obtained even after long-term use. Also, when molded as a continuous nail, it is used in an automatic nailing machine because the pillars of the nail have high bending rigidity and the connecting part that connects the heads of the nails is made of resin and can be easily separated. It can also be suitably used as a continuous spelling type nail. Furthermore, since this nail is composed only of polyamide resin and glass fiber, an inexpensive synthetic resin nail can be provided.

Claims (1)

[Claims] 1. A nail made of a synthetic resin, wherein the synthetic resin is composed of a crystalline polyamide resin and an amorphous polyamide resin in a weight ratio of (crystalline polyamide resin) / (amorphous polyamide resin) = 90. A synthetic resin nail comprising a total of 100% by weight of 30 to 50% by weight of a polyamide resin blended so as to be / 10 to 10/90 and 70 to 50% by weight of glass fiber.