JP6011381B2 - Insulated wire for connector pressure connection using polyvinyl chloride resin composition - Google Patents

Description

The present invention relates to a connector insulation displacement connection for insulated wire using a polyvinyl chloride resin composition.

  An insulated wire includes a conductor and an insulating coating (insulating layer) that covers the conductor, and is used as, for example, an internal wiring of an electric device or the like. The in-device wiring is configured by connecting a plurality of insulated wires to a connector. The connection of the insulated wire to the connector is performed by inserting the insulated wire into the connector and connecting it to the connector terminal.

  Examples of the connection of the insulated wire to the connector include a crimp connection and a pressure contact connection. Crimp connection is a method in which a conductor terminal of an insulated wire is exposed and the exposed conductor and terminal are connected one by one. The press contact connection is a method in which an insulated wire is press-fitted between a blade-shaped terminal and pushed in, and the conductor and the terminal are connected while breaking through the insulating layer by the terminal. According to the press contact connection, it is not necessary to expose the conductor terminal as in the case of the crimp connection, and a plurality of insulated wires can be connected simultaneously at the same time.

  By the way, in recent years, the wiring inside the equipment has also been downsized in response to the downsizing of the electrical equipment, and the insulated wire used for the wiring inside the equipment has been reduced in diameter and narrow pitch (for example, 1.0 mm to 1.5 mm). Tends to be connected to the connector. Due to this tendency, a press-contact connection that can simultaneously connect a plurality of insulated wires to a connector has been adopted.

  In an insulated wire that is press-connected, a large pressure is applied by being press-fitted between terminals. Therefore, the insulating layer is required to have predetermined mechanical characteristics so as not to be deformed by pressure. If the mechanical properties of the insulating layer are low, the insulating layer is deformed, and the insulated wire is difficult to be held by the connector, so that there is a possibility that it will come out of the connector and become poorly conductive.

  As a resin constituting such an insulating layer, there is a polyvinyl chloride resin. Polyvinyl chloride resin is a polar polymer and has a strong intermolecular force, so that it becomes a hard molded product, but it becomes a flexible molded product by adding a plasticizer. That is, the polyvinyl chloride resin becomes a soft polyvinyl chloride resin when a relatively large amount of plasticizer is added, and exhibits flexibility, while it becomes a semi-rigid polyvinyl chloride resin when a relatively small amount of plasticizer is added. The mechanical properties of are shown.

  When high mechanical properties are required for the insulating layer, a semi-rigid polyvinyl chloride resin having a low plasticizer content is used for the insulating layer. When an insulating layer is composed of a semi-rigid polyvinyl chloride resin, a small amount of plasticizer is added to the polyvinyl chloride resin, and the plasticizer is dispersed by kneading to obtain a resin composition, which is then melted by heating. Then, the molten resin composition is formed on the conductor by extrusion. Non-lead stabilizers such as metal soaps such as fatty acid zinc and hydrotalcite are used as thermal stabilizers so that the polyvinyl chloride resin does not deteriorate during heating to melt the resin composition. It is added (see, for example, Patent Document 1).

  However, when an insulated wire is manufactured using a semi-rigid polyvinyl chloride resin, there is a problem that the production rate of the insulated wire is slow and the productivity is low. The production speed of the insulated wire increases as the speed of extruding the resin onto the conductor (extrusion speed) increases. For example, the extrusion speed when extruding a semi-rigid polyvinyl chloride resin with a wall thickness of 0.15 mm or less is 350 m / min. Is the upper limit, and it is difficult to increase productivity by increasing the extrusion speed. This is because the semi-rigid polyvinyl chloride resin contains a relatively small amount of plasticizer, has a high viscosity in a molten state, and has low moldability (extrusion moldability). When a semi-rigid polyvinyl chloride resin having low extrudability is extruded, for example, at an extrusion speed of 400 m / min, the formed insulating layer may be roughened like a shark skin. This phenomenon is a so-called melt fracture, which hinders the press-contact connection of the insulated wire to the connector and reduces not only the processing efficiency but also the applicability of the printing ink.

  In order to improve the extrudability of semi-rigid polyvinyl chloride resin and improve the productivity of insulated wires, it may be possible to adjust the viscosity by increasing the heating temperature at which semi-rigid polyvinyl chloride resin is heated. If the temperature is high, the polyvinyl chloride resin itself may be deteriorated and the originally obtained characteristics may not be obtained. Further, it is conceivable to increase the content of the plasticizer to be added and adjust the viscosity to a low level, but the polyvinyl chloride resin may be softened and the mechanical properties of the resulting insulating layer may be reduced.

  Thus, when manufacturing insulated wires using semi-rigid polyvinyl chloride resin, the viscosity of semi-rigid polyvinyl chloride resin is high and the extrusion moldability is low, so the extrusion speed is limited and the productivity of insulated wires is reduced. It has become difficult to improve.

  In this regard, Patent Documents 2 to 4 propose that polymethyl methacrylate (hereinafter also referred to as PMMA) is added to a polyvinyl chloride resin for the purpose of improving the extrusion moldability. According to Patent Documents 2 to 4, it is possible to improve the extrusion moldability of the polyvinyl chloride resin composition and improve the productivity of the insulated wire.

JP 2004-193138 A JP 2003-327762 A JP 2005-89604 A JP 2005-89605 A

  However, according to the polyvinyl chloride resin compositions of Patent Documents 2 to 4, by adding PMMA or the like as a gelation accelerator, the extrusion property can be improved while maintaining the mechanical properties, but the extrusion speed is increased. Furthermore, it is difficult to increase the speed. That is, the extrusion moldability is insufficient, and when the extrusion speed is further increased, the extruded appearance of the formed insulating layer may be poor. In addition, according to the polyvinyl chloride resin compositions of Patent Documents 2 to 4, there is a problem that the cold resistance is lowered by containing PMMA which is a low molecular weight polymer.

The present invention has been made in view of the above problems, good machine械的characteristics and cold resistance, to provide a connector insulation displacement connection for insulated wire is extruded appearance has good insulating layer is there.

According to a first aspect of the invention,
A polyvinyl chloride resin composition containing a polyvinyl chloride resin (A), a plasticizer (B), and a non-lead stabilizer (C), and containing no polymethyl methacrylate as a gelation accelerator, ,
The lead-free stabilizer (C) includes zinc metal soap (c1) and hydrotalcite (c2),
For 100% by mass of the polyvinyl chloride resin composition,
19% by mass or more and 24% by mass or less of the plasticizer (B),
Containing 4% by mass or more of the non-lead stabilizer (C),
Said zinc metal soap (c1) mass ratio (c2 / c1) is a conductor the outer periphery of the formed insulating layer from 3.5 to 10 der Lupo polyvinyl chloride resin composition of the hydrotalcite (c2) There is provided an insulated wire for connector press-fit connection .

According to a second aspect of the invention,
An insulated wire for connector pressure contact connection according to a first aspect, comprising 4% by mass or more and 20% by mass or less of the non-lead stabilizer (C) is provided.

According to a third aspect of the invention,
The lead-free stabilizer (C) further includes at least one selected from the group consisting of β-diketone compounds, antioxidants, polyhydric alcohols, and metal hydrates, and the total of these is the lead-free stabilizer. The insulated wire for connector pressure contact connection according to the first aspect or the second aspect, which is 50% or less of (C), is provided.

According to a fourth aspect of the invention,
Any one of the first to third aspects, further containing at least one additive (D) selected from the group consisting of a filler and a colorant, and containing 10% by mass or less of the additive (D) An insulated wire for connector pressure connection is provided.

According to a fifth aspect of the present invention,
An insulated wire for connector pressure connection according to any one of the first to fourth aspects is provided, wherein the insulating layer has a thickness of 0.2 mm or less .

According to the present invention, excellent machine械的characteristics and cold resistance, a connector insulation displacement connection for insulated wire is extruded appearance has good insulating layer is obtained.

It is a figure which shows the cross section of the insulated wire for connector press-contact connection which concerns on one Embodiment of this invention.

<Knowledge obtained by the inventor>
Prior to the description of an embodiment of the present invention, the knowledge obtained by the present inventor will be described.

  As described above, the addition of polymethylmethacrylate (hereinafter also referred to as PMMA) as a gelation accelerator to semi-rigid polyvinyl chloride resin is insufficient for extrusion moldability, further increasing the extrusion speed. Then, the extrusion appearance of the insulating layer was deteriorated. In the semi-rigid polyvinyl chloride resin, the low extrudability is caused by the fact that the plasticizer or the like is not uniformly dispersed and the viscosity when heated and melted is not uniform (viscosity unevenness). When the extrusion speed is increased, it is considered that the influence of uneven viscosity increases and the extrusion appearance deteriorates. In this regard, the present inventor changed the kneading conditions (screw and cylinder structure, etc.) as appropriate, and uniformly dispersed the plasticizer, so that the extrusion property of the polyvinyl chloride resin composition and the extrusion of the insulating layer were improved. An attempt was made to improve the appearance, but this could not be achieved when the extrusion speed was increased.

  Since extrudability cannot be improved only by changing the kneading conditions, the present inventor considers that there is a factor in the absorption efficiency of the plasticizer and the dispersion efficiency when using a gelling accelerator other than kneading. , Earnestly examined. As a result, it was considered that these factors included a change in porosity in the polyvinyl chloride resin.

  Here, the porosity indicates the porosity in the polyvinyl chloride resin. The polyvinyl chloride resin has voids with a predetermined porosity (porosity), and if it has sufficient voids, it helps absorb the plasticizer and enables uniform dispersion. When dispersing, add a plasticizer to the polyvinyl chloride resin, absorb it into the voids using a high-speed mixer, and then knead it with a predetermined shear (shearing force) to collapse the polyvinyl chloride particles. Let

  However, in a polyvinyl chloride resin, when kneaded with a predetermined shearing force, voids are often not evenly distributed, and the porosity may change due to local collapse. This can lead to non-uniform plasticizer dispersibility. As a result, the obtained polyvinyl chloride resin composition has a non-uniform viscosity in the molten state, and the extrusion moldability is lowered. Specifically, when the polyvinyl chloride resin is kneaded, the portion where the voids locally collapse becomes the gel portion, while the portion where the void does not collapse becomes the non-gel portion. The ungelled component has a lower plasticizer absorbability than the gel component and tends to have a high viscosity even when melted, which causes the viscosity of the polyvinyl chloride resin to become non-uniform. .

  In particular, when a small amount of plasticizer is dispersed to form a semi-rigid polyvinyl chloride resin, it is difficult to knead (low kneadability), so there is a tendency to increase the shearing force, and the local collapse of voids is promoted. Extrudability will be further reduced.

  In addition, when PMMA or the like is dispersed as a gelling accelerator, PMMA itself acts on the polyvinyl chloride resin particle collapse, but increases the melt viscosity. For example, heat generation is suppressed by kneading with a kneader and a mixing roll. However, the two-stage kneading with the main kneading was necessary, which was inefficient. Moreover, since the addition of PMMA increases the melt tension of the polyvinyl chloride resin, it deteriorates the appearance due to melt fracture and is not suitable for high-speed extrusion of electric wires.

  Thus, when a small amount of plasticizer or gelation accelerator is added to form a semi-rigid polyvinyl chloride resin, the voids locally collapse during kneading to form an ungelled portion, such as a plasticizer. The dispersibility of the resin becomes non-uniform, and the extrudability (molding speed, appearance) of the resulting polyvinyl chloride resin composition decreases.

  Further, the ungel content not only deteriorates the extrusion moldability and prevents the production speed from being increased, but also deteriorates the extrusion appearance of the formed insulating layer. In addition, the non-gel content is less likely to absorb plasticizers and heat stabilizers compared to the gel content, and the rate of thermal degradation is fast. Therefore, if there is an ungel content in the polyvinyl chloride resin, Chlorine is desorbed due to thermal degradation, and degradation of the entire resin is accelerated by the desorbed chlorine.

  In view of this, the present inventor has eagerly devised a method for dispersing a plasticizer and the like in a semi-rigid polyvinyl chloride resin that is difficult to knead while reducing kneading and suppressing local collapse of voids (change in porosity). Study was carried out. As a result of the study, it was found that control of heat resistance and internal / external lubricity in a polyvinyl chloride resin is effective for dispersing a plasticizer while minimizing kneading. That is, the heat resistance and the internal / external lubrication affect the kneadability of the polyvinyl chloride resin composition, and by controlling these, the kneadability can be improved and the dispersibility of the plasticizer and the like can be improved. For this control, by adjusting the mass ratio of the zinc metal soap that imparts heat resistance and internal / external lubrication to the hydrotalcite that complements heat resistance, the dispersibility of plasticizers and the like is made uniform and the extrusion moldability is improved. I found out that I can do it. The present invention has been made based on the above findings.

<One Embodiment of the Present Invention>
An embodiment of the present invention will be described below.

(1) polyvinyl chloride resin composition that is used in this embodiment a polyvinyl chloride resin composition, a polyvinyl chloride resin (A), the plasticizer (B), and zinc metallic soap (c1) and hydrotalcite A lead-free stabilizer (C) containing (c2) and no polymethyl methacrylate as a gelation accelerator. And with respect to 100 mass% of polyvinyl chloride resin compositions, 19 mass% or more and 24 mass% or less of plasticizers (B), 4 mass% or more of non-lead stabilizers (C) are contained, hydrotalcite (c2) ) To zinc metal soap (c1) (c2 / c1) is 3.5 or more and 10 or less.

(Polyvinyl chloride resin (A))
Examples of the polyvinyl chloride resin include homopolymers of vinyl chloride, that is, polyvinyl chloride, copolymers of vinyl chloride and other copolymerizable monomers, and mixtures thereof. As the polyvinyl chloride resin, those having an average degree of polymerization in the range of 1000 to 3000 are preferable. If the average degree of polymerization is less than 1000, mechanical properties and heat resistance may decrease, and if the average degree of polymerization exceeds 3000, extrusion moldability may decrease unless the molten resin temperature during molding is increased. There is.

(Plasticizer (B))
The plasticizer (B) is an additive for imparting flexibility to the polyvinyl chloride resin composition and facilitating processing. The plasticizer (B) is not particularly limited and known ones are used, but trimellitic acid esters are preferable. Specific examples include n-octyl trimellitic acid, tri-2-ethylhexyl trimellitic acid, triisononyl trimellitic acid, triisodecyl trimellitic acid, and the like. Among these, from the viewpoint of imparting cold resistance, n-octyl trimellitic acid having a linear alkyl chain length is more preferable. In order to reduce cost, a part of trimellitic acid n-octyl may be replaced with a side chain trimellitic acid ester.

  The content of the plasticizer (B) is 19% by mass to 24% by mass with respect to 100% by mass of the polyvinyl chloride resin composition. When the content exceeds 24% by mass, the mechanical properties of the polyvinyl chloride resin composition are low, and the formed insulating layer is easily deformed by pressure. On the other hand, when the content is less than 19% by mass, the mechanical properties are high, and the formed insulating layer is not only difficult to press-connect, but the likelihood of cold resistance may be lost.

(Lead-free stabilizer (C))
The non-lead stabilizer (C) is a heat stabilizer and suppresses the deterioration of the polyvinyl chloride resin composition by desorbing hydrogen chloride when heated and kneaded. The content of the lead-free stabilizer (C) is 4% by mass or more with respect to 100% by mass of the polyvinyl chloride resin composition. When the content is less than 4% by mass, it becomes difficult to maintain the thermal stability at the time of kneading or extruding the polyvinyl chloride resin composition, and the formed insulating layer is burned, resulting in poor appearance. Moreover, although the upper limit of content of a non-lead stabilizer (C) is not specifically limited, It is preferable that it is 20 mass% or less. By setting it as 20 mass% or less, foaming and coloring of the insulating layer formed can be suppressed.

  In the present embodiment, as described above, the heat resistance and the internal / external lubricity of the polyvinyl chloride resin composition are controlled so that the plasticizer (B) can be uniformly dispersed while minimizing kneading. For this control, the lead-free stabilizer (C) contains zinc metal soap (c1) that imparts heat resistance and internal / external lubricity, and hydrotalcite (c2) that supplements heat resistance. Each will be described below.

  Zinc metal soap (c1) is a main stabilizer and consists of aliphatic carboxylic acid (fatty acid) and zinc. Zinc metal soap (c1) has high compatibility with the polyvinyl chloride resin composition and good dispersibility. Moreover, while giving internal / external lubricity to a polyvinyl chloride resin composition, predetermined heat resistance is provided. Although it does not specifically limit as a zinc metal soap (c1), What consists of a C12-C24 fatty acid and zinc is preferable, for example, a zinc stearate and a zinc laurate are mentioned. According to such a zinc metal soap (c1), the zinc content is 7% by mass or more and 15% by mass or less, and the zinc content in the resin composition is added even when the zinc content is added at a predetermined content. Does not increase excessively. That is, a decrease in heat resistance due to an increase in the zinc content in the resin composition can be suppressed. In addition, two or more types of zinc metal soaps may be used in combination.

  Hydrotalcite (c2) is a stabilizing aid, suppresses deterioration by the action of hydrogen chloride scavenging, and improves the heat resistance of the polyvinyl chloride resin composition. Hydrotalcite (c2) complements the heat resistance obtained by zinc metal soap (c1) by being combined with zinc metal soap (c1). Although it does not specifically limit as hydrotalcite (c2), The intensity ratio (Mg / Al) of magnesium (Mg) and aluminum (Al) by fluorescent X-ray analysis is controlled between 1 and 1.2. Those are preferred. This is because if the magnesium content increases, the coloration tends to be easier, and if the Al content increases, the dehydration start point becomes earlier and foaming occurs.

In the lead-free stabilizer (C), the mass ratio (c2 / c1) of the hydrotalcite (c2) to the zinc metal soap (c1) is 3.5 or more and 10 or less. Preferably it is 3.5 or more and 7.5 or less. When (c2 / c1) is less than 3.5, the content of zinc metal soap (c1) is relatively increased, and the external slip of the polyvinyl chloride resin composition becomes excessive, and the polyvinyl chloride resin composition Becomes difficult to gel uniformly. That is, the polyvinyl chloride resin composition has a non-uniform viscosity, the extrusion moldability is lowered, and the extrusion appearance of the formed insulating layer and the like becomes poor. On the other hand, if (c2 / c1) exceeds 10, foaming may occur when the polyvinyl chloride resin composition is extruded, and temperature adjustment is required when extruding.
Thus, as for the polyvinyl chloride resin composition used for this embodiment, mass ratio (c2 / c1) is in a predetermined range, and heat resistance and internal / external lubricity are adjusted. For this reason, the plasticizer (B) and the lead-free stabilizer (C) are uniformly dispersed, the viscosity nonuniformity (viscosity unevenness) when melted is suppressed, and the extrusion moldability is excellent. The formed insulating layer has a good extrusion appearance.

  The lead-free stabilizer (C) is a group consisting of a β-diketone compound, an antioxidant, a polyhydric alcohol, and a metal hydrate in addition to the zinc metal soap (c1) and the hydrotalcite (c2). It may further contain at least one selected from the compound (c3)). Compound (c3) is further combined with zinc metal soap (c1) and hydrotalcite (c2) to further complement thermal stability and further improve the extrusion moldability of the polyvinyl chloride resin composition. In particular, β-diketone compounds are preferably added because they are highly compatible with the polyvinyl chloride resin composition and can improve the stability of the zinc metal soap (c1). The total content of the compound (c3) is preferably 50% or less of the non-lead stabilizer (C). That is, the total of the zinc metal soap (c1) and the hydrotalcite (c2) is preferably 50% or more of the non-lead stabilizer (C).

  Although it does not specifically limit as a beta-diketone compound, For example, dibenzoyl methane (DBM) and stearyl benzoyl methane (SBM) are mentioned. The content of the β-diketone compound is preferably 0.5% by mass or less in consideration of the photosensitization property of the insulating layer to be formed.

  Antioxidants are not particularly limited, but there are primary antioxidants such as phenols having a radical scavenging action, and secondary antioxidants such as sulfur having a peroxide decomposing action, and these are used alone. These may be used in combination. Preferably, any one of them is used in combination. The content of the antioxidant is preferably 0.5% by mass or less so that blooming does not occur in the polyvinyl chloride resin composition.

  The phenolic primary antioxidants include primary antioxidants classified into monophenolic, bisphenolic, and polyphenolic types. Examples of the monophenol-based primary antioxidant include 2,2′-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol, and mono (α-methylbenzyl). ) And the like. Examples of bisphenol-based primary antioxidants include 2,2′-methylenebis (4-methyl-6-tert-butylphenol), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4 , 4′-butylidenebis (3-methyl-6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol), butylated reaction product of p-cresol and dicyclopentadiene, Or di ((alpha) -methylbenzyl) etc. are mentioned. Furthermore, examples of the polyphenol-based primary antioxidant include 2,5'-di-t-butylhydroquinone, 2,5'-di-t-amylhydroquinone, and tri (α-methylbenzyl).

  Sulfur-based secondary antioxidants include secondary antioxidants classified into benzimidazole-based, dithiocarbamate-based, thiourea-based, and organic thioacid-based systems. Examples of the benzimidazole-based secondary antioxidant include 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, and zinc salt of 2-mercaptobenzimidazole. Examples of the dithiocarbamate-based secondary antioxidant include nickel diethyldithiocarbamate and nickel dibutyldithiocarbamate. Furthermore, examples of the thiourea-based secondary antioxidant include 1,3-bis (dimethylaminopropyl) -2-thiourea and tributylthiourea. Furthermore, examples of the organic thioacid-based secondary antioxidant include dilauryl thiodipropionate.

  The polyhydric alcohol is not particularly limited, and examples thereof include pentaerythritol, dipentaerythritol, tripentaerythritol, tetrapentaerythritol, sorbitol, glycerin, and polyglycerin. Moreover, what esterified and etherified some hydroxyl groups of these polyhydric alcohols is also mentioned. The content of the polyhydric alcohol is preferably 0.5% by mass or less so that bleed-out does not occur when forming an insulating layer or the like.

  The metal hydrate is not particularly limited, and examples thereof include calcium hydroxide, aluminum hydroxide, and magnesium hydroxide. Aluminum hydroxide is preferable from the viewpoint of suppressing coloring of the insulating layer. From the viewpoint of hydrogen chloride scavenging action during processing of the polyvinyl chloride resin composition, calcium hydroxide and magnesium hydroxide are preferred. These may be used in combination of two or more instead of one. In addition, content of metal hydrate is not specifically limited, It can change suitably.

(Additive (D))
In addition to the plasticizer (B) and the lead-free stabilizer (C), the polyvinyl chloride resin composition used in this embodiment is at least one additive (D) selected from the group consisting of fillers and colorants. May be contained. The content of the additive (D) is preferably 10% by mass or less. When the content of the additive (D) exceeds 10% by mass, the viscosity during extrusion molding of the polyvinyl chloride resin composition increases, so that the extrusion appearance of the formed insulating layer and the like may be poor.

  The filler is not particularly limited as long as it reduces the content of the polyvinyl chloride resin composition in the insulating layer and suppresses the cost. Examples thereof include calcium carbonate and silicic acid (silicic acid compound). Calcium carbonate can be either heavy or light. In the case of heavy calcium carbonate, the average particle size is preferably 10 μm or less in order to improve the appearance of the insulating layer. The silicic acid (silicic acid compound) is not particularly limited as long as it is produced by a synthesis method, and aluminum silicate (calcined clay) obtained by kaolinite sintering at a high temperature may be used.

  The colorant is not particularly limited, and examples thereof include granular processed pigments and color master batches.

(2) Manufacturing method of polyvinyl chloride resin composition The manufacturing method of the polyvinyl chloride resin composition used for the said embodiment is demonstrated.

  First, a plasticizer (B) and a non-lead stabilizer (C) are added to the polyvinyl chloride resin (A) so as to have a predetermined content. At this time, zinc metal soap (c1) and hydrotalcite (c2) are used as the lead-free stabilizer (C), and their mass ratio (c2 / c1) is 3.5 to 10, preferably 3. Each addition amount is determined so that it may become 5 or more and 7.5 or less.

  Next, the mixture is kneaded to produce a polyvinyl chloride resin composition. When kneading, rough kneading is performed using an internal mixer or a kneader. The rough kneading conditions may be a chamber temperature of 110 ° C. to 140 ° C., for example, 30 rpm or less for a rotor (screw) and 60 rpm or less for an internal mixer. In this embodiment, the heat resistance and the internal / external lubricity of the polyvinyl chloride resin composition are controlled by setting the mass ratio of the zinc metal soap (c1) and the hydrotalcite (c2) to a predetermined numerical range. Thereby, a plasticizer (B) can be disperse | distributed, without performing kneading | mixing in two steps, rough kneading and main kneading. In addition, since the local collapse of the voids can be suppressed while minimizing the kneading, the dispersion of the plasticizer (B) and the like can be made uniform. That is, in this embodiment, the plasticizer (B) and the like can be uniformly dispersed, and a polyvinyl chloride resin composition excellent in extrusion moldability can be obtained. In addition, it is possible to simplify the manufacturing process by omitting conventionally required training.

  The plasticizer (B) and the lead-free stabilizer (C) may be added at the same time, but after adding the lead-free stabilizer (C) and mixing, the plasticizer (B) is added and kneaded. Also good. Moreover, an additive (D) may be added simultaneously with a plasticizer (B), and may be added previously before addition of a plasticizer (B).

  The kneading time is not particularly limited. According to the polyvinyl chloride resin composition of the present embodiment, since the plasticizer is uniformly absorbed, that is, the plasticizer can be uniformly dispersed, so that the influence of the kneading time is small. The kneading time is, for example, about 600 seconds, but may be 120 to 180 seconds earlier or may be about 240 to 300 seconds later.

(3) connector insulation displacement connection for insulated wire will now be described connector insulation displacement connection for insulated wire according to an embodiment of the present invention. The insulated wire for connector pressure connection of the present embodiment has an insulating layer composed of the polyvinyl chloride resin composition. Specifically, as shown in FIG. 1, the insulated wire 1 for connector pressure connection has a conductor 11 and an insulating layer 12 formed on the outer periphery of the conductor 11 and made of the polyvinyl chloride resin composition. .

The material of the conductor 11 is not particularly limited, and is formed from a metal material such as copper or a copper alloy, for example. Further, the conductor diameter is not particularly limited, and an optimum one can be appropriately selected according to the application . Guide Karada径is preferably in small diameter is preferably, for example, 0.2mm or 0.6mm or less.

  The insulating layer 12 covers the outer periphery of the conductor 11 and is made of the polyvinyl chloride resin composition. The insulating layer 12 is formed by extruding a polyvinyl chloride resin composition melted by heating around the conductor 11. When the insulating layer 12 is formed, the conductor 11 is sent out at a predetermined extrusion speed. In this embodiment, since the polyvinyl chloride resin composition having excellent extrusion moldability is used, the conductor 11 is extruded with a wall thickness of 0.15 mm, for example. The upper limit of the extrusion speed at that time can be set to 500 m / min.

  The thickness of the insulating layer 12 is not particularly limited, and an optimum thickness is selected according to the application. In the case of pressure connection to the connector, since the outer diameter of the insulated wire 1 is preferably small, the thickness of the insulating layer 12 is preferably 0.2 mm or less, more preferably 0.1 mm or more and 0.2 mm or less. . Since the insulating layer 12 is made of a polyvinyl chloride resin composition exhibiting high mechanical properties, even when the thickness is small, the insulating layer 12 exhibits mechanical properties that are not deformed by the pressure of the pressure connection.

<Effects of Embodiment of the Present Invention>
According to the present embodiment, the following one or more effects are achieved.

According to the polyvinyl chloride resin composition used in this embodiment, the polyvinyl chloride resin composition comprises 19% by mass or more and 24% by mass or less of the plasticizer (B), and 4% by mass of the non-lead stabilizer (C). Contains above. In addition, zinc metal soap (c1) and hydrotalcite (c2) as the lead-free stabilizer (C) are contained in a mass ratio (c2 / c1) of 3.5 or more and 10 or less. Thereby, since a plasticizer (B) etc. are disperse | distributing uniformly, the viscosity in the molten state is uniform and it is excellent in extrusion moldability. In addition, since it does not contain a low-molecular polymer such as a gelation accelerator, it has excellent cold resistance, and since the content of the plasticizer (B) is relatively small, it has excellent mechanical properties.

Moreover, according to the polyvinyl chloride resin composition used for this embodiment , it is preferable that a polyvinyl chloride resin composition contains 4 to 20 mass% of non-lead stabilizers (C). Thereby, deterioration of the extrusion appearance due to foaming or coloring can be suppressed, and the extrusion appearance can be improved.

Further , according to the polyvinyl chloride resin composition used in the present embodiment, the lead- free stabilizer (C) is selected from the group consisting of β-diketone compounds, antioxidants, polyhydric alcohols, and metal hydrates. It is preferable that the total of these is further 50% or less of the non-lead stabilizer (C). Thereby, extrusion moldability can further be improved.

In addition, according to the polyvinyl chloride resin composition used in the present embodiment , it further contains at least one additive (D) selected from the group consisting of a filler and a colorant, and the additive (D) It is preferable to contain 10 mass% or less. According to the filler, since the proportion of the polyvinyl chloride resin composition can be reduced, the cost can be reduced. Further, according to the colorant, the appearance of the insulating layer and the like can be changed as appropriate.

Further , according to the polyvinyl chloride resin composition used in the present embodiment, zinc metal soap (c1) and hydrotalcite (c2) are added at a predetermined mass ratio, and the heat resistance of the polyvinyl chloride resin composition is increased. Therefore, the plasticizer (B) and the like can be uniformly dispersed only by rough kneading. That is, it is possible to omit the conventionally required training, and the manufacturing process can be simplified.

Moreover, according to this embodiment , the insulated wire for connector pressure connection has an insulating layer comprised from the said polyvinyl chloride resin composition. Thereby, it is possible to obtain an insulated wire for connector press-contact connection which is excellent in mechanical properties and cold resistance and has a good extruded appearance. Further, since the insulating layer is formed from a polyvinyl chloride resin composition having excellent mechanical properties, even if the thickness is 0.2 mm or less, deformation is hardly caused by the pressure of the pressure connection. That is, in the insulated wire of this embodiment, the disconnection from the connector is suppressed, and poor conduction is unlikely to occur.

  Next, examples of the present invention will be described. In this example, a polyvinyl chloride resin composition was prepared and an insulated wire was manufactured using the composition. And the polyvinyl chloride resin composition was evaluated by measuring the cold resistance of the obtained insulated wire, the extrusion appearance, and the pressure contact property of the insulated wire. These examples are examples of the present invention, and the present invention is not limited to these examples.

  The materials used in the following examples and comparative examples are as follows.

The following were used as the polyvinyl chloride resin (A).
Polyvinyl chloride resin: “TK-1300” manufactured by Shin-Etsu Chemical (average polymerization degree 1300)

The following were used as the plasticizer (B).
Tri-n-octyl trimetate: “N-08” manufactured by Kao
Tri-2-ethylhexyl trimetate: “T-08” manufactured by Kao

The following were used as zinc metal soap (c1) which is a non-lead stabilizer (C).
Zinc laurate: Nitto Kasei "ZS-3" (zinc content 14%)
Zinc stearate: Nitto Kasei "Zn-St" (zinc content 10.7%)

The following were used as hydrotalcite (c2) which is a non-lead stabilizer (C).
Hydrotalcite: Sakai Chemical "HT-1"

The following were used as β-diketone compounds which are non-lead stabilizers (C).
Dibenzoylmethane (DBM): manufactured by Tokyo Chemical Industry

The following were used as antioxidant which is a non-lead stabilizer (C).
Phenolic antioxidant: “1010” manufactured by BASF

The following were used as polyhydric alcohol which is a non-lead stabilizer (C).
Dipentaerythritol: Guangei Chemical Industry

The following were used as a metal hydrate which is a non-lead stabilizer (C).
Calcium hydroxide: “Kalmu Mesox” by Yoshizawa Lime Industry

The following were used as additive (D).
Calcium carbonate: “Softon 2200” manufactured by Bihoku Flour Industry
Silica: Nippon Aerosil “R972”
Color master batch: MS series made by Dainichi Seika

(2) Preparation of polyvinyl chloride resin composition Using the above materials, the polyvinyl chloride resin compositions of Examples 1 to 5 were prepared. The adjustment conditions are shown in Table 1 below.

  In Examples 1-5, the polyvinyl chloride resin composition was adjusted with the adjustment conditions shown in Table 1. Specifically, a material other than the plasticizer was added to the polyvinyl chloride resin and mixed at 60 ° C. with a 200 L high-speed mixer (manufactured by Kawata) to obtain a resin mixture. Then, the plasticizer was added to the resin mixture, and it was made to dry up by raising the resin temperature to 100 degreeC as a polyvinyl chloride resin composition. The dried-up polyvinyl chloride resin composition was coarsely kneaded for about 600 seconds using a 3 L kneader (manufactured by Moriyama), and a pellet molded product was obtained using a cooler and an air-cooled granulator (manufactured by Moriyama). The kneading conditions were a chamber temperature of 130 ° C., a kneader screw speed of 30 rpm, and a resin discharge temperature of 170 ° C.

  Moreover, the polyvinyl chloride resin composition of Comparative Examples 1-6 was prepared using the said material. The adjustment conditions are shown in Table 2 below.

  In Comparative Example 1 and Comparative Example 2, adjustment was performed in the same manner as in Example 1 except that polymethyl methacrylate (Made by Mitsubishi Rayon, P-710) was added as a gelation accelerator.

  In Comparative Example 3, adjustment was made in the same manner as Comparative Example 1 except that the kneading conditions of Comparative Example 1 were changed and main kneading was added to the rough kneading. Specifically, the polyvinyl chloride resin composition of Comparative Example 1 obtained by rough kneading is finally kneaded for about 300 seconds with a mixing roll (8-inch roll manufactured by Nishimura Koki Co., Ltd.). Pellet molded product was obtained.

  In Comparative Example 4, adjustment was made in the same manner as in Example 1 except that the content of the plasticizer (B) was larger than 24% by mass.

  In Comparative Example 5, the zinc metal soap (c1) and the hydrotalcite (c2) had a mass ratio (c2 / c1) of the hydrotalcite (c2) to the zinc metal soap (c1) of less than 3.5. Except having changed content, it adjusted similarly to Example 1. FIG.

  In Comparative Example 6, adjustment was made in the same manner as in Example 1 except that the content of the lead-free stabilizer (C) was less than 4% by mass.

(3) Production of insulated wire Next, an insulated wire was produced using the polyvinyl chloride resin composition obtained above. Specifically, a tin-plated conductor (outer diameter 0.48 mm, size 26 AWG of configuration 7 / 0.16) as a conductor is sent out at a predetermined linear speed, and the insulating layer has a thickness of 0.15 mm on the outer periphery. Then, the polyvinyl chloride resin composition was extruded by a 50 mmEXT extruder (manufactured by Omiya Seiki Co., Ltd.) to produce an insulated wire having an outer diameter of 0.78 mm. In the present example, the linear velocity at which the conductor was sent out was 400 m / min, and the extrusion speed was 400 m / min.

(4) Evaluation method Next, the following method evaluated the polyvinyl chloride resin composition obtained above, and the insulated wire using the same. Each evaluation method will be described below.

(Cold resistance)
A sheet of the polyvinyl chloride resin composition formed into a mixin gall and pressed to a thickness of 0.5 mm was prepared, and the embrittlement temperature of the sheet was measured. As a criterion for the embrittlement temperature, those with −15 ° C. or less that passed the UL standard (758) with a likelihood were evaluated as “◯”.

(Extrudability)
As evaluation of extrusion moldability, the upper limit of the extrusion speed of the resin composition was measured.

(Extruded appearance)
About the obtained insulated wire, there was no problem in the applicability of the printing ink, the appearance of the touch was good, and the spark missing and the hump defect did not occur continuously for 1 hour or more were evaluated as “◯”. In addition, poor appearance due to burns or the like was also used as an index of extrusion appearance.

(Press contact)
The obtained insulated wire is press-contacted to a CZ connector (1.5 mm pitch), and there is no breakage, deformation, and all pass the pull-out test. This was designated as “x”.

(5) Evaluation results The evaluation results of Examples 1 to 5 and Comparative Examples 1 to 6 are shown in Table 3 below.

  In each of Examples 1 to 5, it was confirmed that the embrittlement temperature was lower than −15 ° C. and the cold resistance was excellent. The upper limit of the extrusion speed was 500 m / min in Example 1, 400 m / min in Example 2, 400 m / min in Example 3, 400 m / min in Example 4, and 400 m / min in Example 5. It was. For this reason, even when the extrusion speed was increased to 400 m / min, it was confirmed that the extruded appearance of the formed insulating layer was good and the extrusion moldability was excellent. In addition, it was confirmed that the manufactured insulated wire has excellent mechanical properties of the insulating layer, so that it does not break or deform and is excellent in press contact.

  In Comparative Example 1 and Comparative Example 2, since PMMA was contained as a gelation accelerator, it was confirmed that the embrittlement temperature was higher than −15 ° C. and the cold resistance was inferior. Moreover, it was confirmed that the extrusion appearance of the formed insulating layer is poor. In Comparative Example 1 and Comparative Example 2, although the extrusion moldability is improved by containing PMMA, the upper limit of the extrusion speed is 150 m / min in Comparative Example 1 and 150 m / min in Comparative Example 2, It was confirmed that the moldability was insufficient. For this reason, it was confirmed that when the extrusion speed was increased to 400 m / min, the extruded appearance of the formed insulating layer deteriorated. In addition, since it has a predetermined mechanical characteristic, it was confirmed that press contact property is favorable.

  In Comparative Example 3, the cold resistance was improved by adding the main kneading to the polyvinyl chloride resin composition of Comparative Example 1, but the extrusion appearance could not be improved. In Comparative Example 3, it was confirmed that the upper limit of the extrusion speed was 250 m / min.

  In Comparative Example 4, since the content of the plasticizer was large, it was confirmed that the mechanical properties of the obtained insulating layer were inferior and the press contact property was poor. In Comparative Example 4, it was confirmed that the upper limit of the extrusion speed was 400 m / min.

  In Comparative Example 5, the mass ratio (c2 / c1) of the hydrotalcite (c2) to the zinc metal soap (c1) was less than 3.5, and the content of the zinc metal soap (c1) was large. As a result, in Comparative Example 5, the zinc metal soap (c1) is excessively slippery and the polyvinyl chloride resin composition is not uniformly gelled, so that the extrusion moldability is lowered and the formed insulating layer is extruded. It is thought that the appearance was poor. In Comparative Example 5, it was confirmed that the upper limit value of the extrusion speed was 100 m / min.

  In Comparative Example 6, since the content of the lead-free stabilizer (C) was small, it is considered that the extrusion moldability was lowered and the extrusion appearance of the formed insulating layer was poor. In Comparative Example 6, it was confirmed that the upper limit of the extrusion speed was 200 m / min.

Thus, according to the present invention, the plasticizer (B) and the lead-free stabilizer (C) are made to have a predetermined content, and the mass ratio between the zinc metal soap (c1) and the hydrotalcite (c2) is set. predetermined value ranges and to Lupo re vinyl chloride resin composition or we formed an insulated layer is extruded appearance is good, excellent mechanical properties and cold resistance. And since the insulated wire which has this insulating layer is a case where it is the case of press-contact connection, since it is hard to deform | transform, it is hard to produce the conduction | electrical_connection defect by omission.

1 Insulated wire for connector pressure connection 11 Conductor 12 Insulating layer

Claims (5)

A polyvinyl chloride resin composition containing a polyvinyl chloride resin (A), a plasticizer (B), and a non-lead stabilizer (C), and containing no polymethyl methacrylate as a gelation accelerator, ,
The lead-free stabilizer (C) includes zinc metal soap (c1) and hydrotalcite (c2),
For 100% by mass of the polyvinyl chloride resin composition,
19% by mass or more and 24% by mass or less of the plasticizer (B),
Containing 4% by mass or more of the non-lead stabilizer (C),
Said zinc metal soap (c1) mass ratio (c2 / c1) is a conductor the outer periphery of the formed insulating layer from 3.5 to 10 der Lupo polyvinyl chloride resin composition of the hydrotalcite (c2) An insulated wire for connector pressure connection, comprising: 2. The insulated wire for connector pressure connection according to claim 1, wherein the lead-free stabilizer (C) is contained in an amount of 4% by mass or more and 20% by mass or less . The lead-free stabilizer (C) further includes at least one selected from the group consisting of β-diketone compounds, antioxidants, polyhydric alcohols, and metal hydrates, and the total of these is the lead-free stabilizer. 3. The insulated wire for connector pressure contact connection according to claim 1 , wherein the insulated wire is 50% or less of (C) . 4. 4. The composition according to claim 1, further comprising at least one additive (D) selected from the group consisting of a filler and a colorant, and further containing 10% by mass or less of the additive (D). An insulated wire for connector pressure connection according to claim 1. The insulated wire for connector pressure contact according to any one of claims 1 to 4, wherein a thickness of the insulating layer is 0.2 mm or less.

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