JP2011207973A - Pvc master batch for regenerated vinyl chloride resin composition, vinyl chloride resin composition, electric wire and cable, method for producing regenerated vinyl chloride resin composition, and method for producing electric wire and cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PVC master batch for a regenerated vinyl chloride resin composition capable of recycling lead-free PVC without deteriorating material characteristics, a vinyl chloride resin composition, an electric wire and cable, a method for producing a regenerated vinyl chloride resin composition, and a method for producing an electric wire and cable.SOLUTION: The PVC master batch for a regenerated vinyl chloride resin composition, which is added to recovered vinyl chloride resin to obtain a regenerated vinyl chloride resin composition, contains a plasticizer in an amount of ≥50 phr, hydrotalcite in an amount of 5-30 phr, and an antioxidant in an amount of 3-20 phr, with respect to the amount of the regenerated vinyl chloride resin.

Description

  The present invention relates to a PVC masterbatch for recycled vinyl chloride resin composition, recycled vinyl chloride resin composition, electric wire / cable, and recycled for recycling recycled products of lead-free recovered vinyl chloride (PVC) resin, wire stripping scraps, etc. The present invention relates to a method for producing a vinyl chloride resin composition and a method for producing an electric wire / cable.

  Conventional PVC materials for wire coating use PVC compounds that use lead compounds as stabilizers. However, lead-free materials have been promoted due to increasing environmental friendliness, and are now almost replaced by lead-free materials. .

  However, the recycling of lead-free materials such as overflow products and stripped products has not been established because no material has been developed that can achieve the same level of stability as lead compounds. This leads to an increase in material costs and a decrease in resource reuse efficiency.

  Conventional recycling methods for PVC containing lead-based compounds have been used as recycled vinyl chloride resin compositions by mixing recovered vinyl chloride with a new vinyl chloride resin of virgin at a certain ratio (Patent Documents 1 to 3). This is because the new vinyl chloride resin provides a dilution effect and improves material properties.

JP 2002-226657 A JP 2002-363364 A JP 2002-167487 A

  However, when this method is applied to a lead-free recovered vinyl chloride resin, the quality of the recovered vinyl chloride resin may deteriorate the properties of the new virgin vinyl chloride resin, which is not an effective method.

  Accordingly, an object of the present invention is to solve the above-mentioned problems and to recycle and reuse the lead-free recovered vinyl chloride resin without deteriorating the material properties. It is providing the manufacturing method of a thing, an electric wire and a cable, a reproduction | regeneration vinyl chloride resin composition, and the manufacturing method of an electric wire and a cable.

  In order to achieve the above-mentioned object, the invention of claim 1 adds to the recovered vinyl chloride resin, and in a PVC masterbatch for obtaining a recycled vinyl chloride resin composition, the plasticizer is added to 50 phr with respect to the novel vinyl chloride resin. As mentioned above, it is a PVC masterbatch for the regenerated vinyl chloride resin composition characterized by containing 5-30 phr hydrotalcite and 3-20 phr antioxidant.

  The invention of claim 2 is the PVC masterbatch for a regenerated vinyl chloride resin composition according to claim 1, wherein the antioxidant is a phenolic antioxidant.

  The invention of claim 3 is a recycled vinyl chloride resin composition comprising 1 to 10 phr of the PVC masterbatch for recycled vinyl chloride resin composition according to claim 1 or 2 with respect to the recovered vinyl chloride resin. It is a thing.

  The invention according to claim 4 is an electric wire / cable characterized by using the recycled vinyl chloride resin composition according to claim 3 as a coating material.

The invention of claim 5 is a step of producing a PVC masterbatch by adding 50 phr or more of a plasticizer, 5 to 30 phr of hydrotalcite, and 3 to 20 phr of an antioxidant to a novel vinyl chloride resin,
A step of producing a recycled vinyl chloride resin composition by melting and kneading the recovered vinyl chloride resin and the PVC master batch;
It is a manufacturing method of the reproduction | regeneration vinyl chloride resin composition characterized by including.

  The invention according to claim 6 is the method for producing a regenerated vinyl chloride resin composition according to claim 5, further comprising extrusion-coating the regenerated vinyl chloride resin composition.

  According to the present invention, the lead-free recovered vinyl chloride resin overflow pulverized product and wire scrap pulverized product can be used as a recycled vinyl chloride resin composition without deteriorating material properties and extrusion processability. To do.

  Hereinafter, a preferred embodiment of the present invention will be described in detail.

  Here, the recovered vinyl chloride resin is an overflow material or a resin material obtained from a resin molded body recovered after being distributed to the market. New vinyl chloride resin is an unused resin material.

  The present invention recycles recycled vinyl chloride resin without degrading material properties by adding a PVC masterbatch to recovered vinyl chloride resin such as lead-free overflow products and wire stripping scraps.

  The PVC masterbatch contains 50 phr or more of a plasticizer such as a phthalate ester type, 5 to 30 phr of a hydrotalcite, and 3 to 20 phr of an antioxidant such as a phenol type for a new vinyl chloride resin. These total amounts consist of 20-60 mass%.

  1-10 phr of this PVC master batch is added to the recovered vinyl chloride resin to obtain a recycled vinyl chloride resin composition.

  Next, the background to the present invention will be described.

About recovered vinyl chloride resin (PVC material for wire coating):
The PVC material for electric wires is an admixture comprising a PVC resin, a plasticizer, a stabilizer, a flame retardant, a filler and the like. In order to disperse these uniformly, a step of granulating after kneading at about 130 to 190 ° C. is required. Moreover, in order to make the granulated pellet into an electric wire shape, a step of coating and extruding the material to the conductor at about 140 to 195 ° C. is also required.

  Thus, the PVC material is accompanied by two thermal histories until it is formed into a covering material for electric wires.

About playback:
In order to recycle the lead-free recovered vinyl chloride resin, as described above, the material that has been subjected to two thermal histories, that is, the overflow material or the practical electric wire scraps generated in the insulation extrusion process or the shell extrusion process is reused. .

  However, such materials have been considered difficult to regenerate due to the following problems.

Problems during playback:
The recovered overflow materials and wire scrap materials have different compounding prescriptions for each member, i.e., the plasticizer, heat stabilizer and filler are different in type and amount added. When performing, a higher shearing heat generation occurs than when kneading ordinary virgin materials.

This shear heat is
(Resin molding resin temperature) − (Virgin material molding resin temperature) = 10 to 15 ° C.
This is because it is higher by 10 to 15 ° C. than the molding resin temperature of the virgin material.

  Since PVC containing lead that has been used so far has good thermal stability in the vicinity of the resin temperature at the time of molding even after two or more thermal histories, recovered chloride consisting of overflow material and wire scrap material Vinyl resin and virgin new vinyl chloride resin have been mixed and reused at a certain ratio.

  However, since the lead-free recovered vinyl chloride resin is subjected to the third thermal history as compared with the lead-containing recovered vinyl chloride resin, the thermal stability rapidly deteriorates.

In other words, lead-free recovered vinyl chloride resin
Virgin kneading (1 time)-Electric wire extrusion (2 times)-Overflow, wire stripping product re-kneading (3 times)
And receive 3 heat histories.

  Since the recovered vinyl chloride resin is repeatedly used in this way, this problem has been a bottleneck.

  In addition, when lead-free recovered vinyl chloride resin that has undergone a thermal history of 3 times or more is used, even if it is mixed with virgin lead-free new vinyl chloride resin at a certain ratio, I did not meet the standards for materials.

These factors are as follows: (1) The raw material in the new vinyl chloride resin that suppresses dehydrochlorination and plasticizer decomposition at high temperatures is consumed when reworking overflow and wire stripping waste.

  (2) Since zinc chloride produced as a by-product is an electrolyte, necessary electrical characteristics cannot be obtained.

  Another example is that this accelerates dehydrochlorination of the vinyl chloride resin.

  Therefore, the present inventor is capable of low-temperature processing (small amount of dehydrochlorination), efficiently capturing dehydrochlorination during high-temperature processing, suppressing zinc chloride formation, and preventing oxidative degradation of the plasticizer. The present invention has been found.

  That is, a PVC masterbatch comprising a plasticizer addition amount of 50 phr or more, a hydrotalcite addition amount of 5 to 30 phr, and a phenolic antioxidant addition amount of 3 to 20 phr was used as a lead-free recovered vinyl chloride resin. On the other hand, 1 to 10 phr is added to obtain a regenerated vinyl chloride resin composition.

  Examples of the plasticizer include phthalate-based DINP, but non-phthalic acid-based plasticizers (trimellitic acid ester, adipic acid polyester, cyclohexanedicarboxylic acid ester, etc.) may be used. Further, a mixed system of phthalate ester and non-phthalate ester may be used.

  In addition to using a phenolic antioxidant, the antioxidant may be a thioether, a phosphite antioxidant, or a mixture thereof.

  As mentioned above, in this invention, a plasticizer contributes to the dispersibility improvement effect at the time of knead | mixing a PVC masterbatch, and while an antioxidant prevents the oxidative degradation of a plasticizer, hydrotalcite serves as a dehydrochlorination scavenger. It functions and exhibits its effect especially in the high temperature range (around 195 ° C.) during reprocessing.

  Examples of the present invention and comparative examples will be described below.

  In both the examples and the comparative examples, first, (a) a PVC masterbatch for lead-free recycled vinyl chloride resin composition is prepared, and (b) a recycled vinyl chloride resin composition is prepared using the PVC masterbatch. (C) Extruded as a wire covering material, and its characteristics were examined.

(A) Production of PVC masterbatch for recycled vinyl chloride resin composition A PVC masterbatch having the composition shown in Table 1 was produced by the following method.

  Master batches a1 to a7 were prepared with the composition shown in Table 1.

  In each master batch a1 to a7, the resin, plasticizer, stabilizer, and other raw materials are weighed and added to a high-speed stirrer (Henschel mixer) so that the total amount becomes 100 parts by mass, and the resin temperature rises to 110 ° C. And then cooled to 40 ° C.

  Next, 80 kg of the cooled mixture is charged into a 75-L batch-type kneader, kneaded at a batch mixer chamber temperature of 150 ° C. and a rotor rotation speed of 50 rpm, and the resin temperature in the mixer is 170 ° C. Was completed.

  The kneaded material was put into a 150 mm uniaxial granulation extruder, granulated, and then air-cooled to obtain a PVC master batch made of a PVC resin composition.

  The conditions of the single screw granulation extruder were as follows: air temperature granulation so that the cylinder temperature was 130 to 170 ° C., the head was 170 ° C., the screen mesh was 40 M, and the molded product was 3 mmφ × 3 mmH.

(B) Production of Recycled Vinyl Chloride Resin Composition A regenerated vinyl chloride resin composition was produced using the PVC master batch shown in Table 1.

  In Comparative Examples 2 to 5 and Examples 1 to 7, the overflow pulverized product (3 to 5 mm square) was 50 parts by mass and the electric wire scrap pulverized product (3 to 5 mm square) was 50 parts by mass. The master batches a1 to a7 were added and mixed. In Comparative Example 1, 50 parts by mass of the virgin compound for general sheath was added to 50 parts by mass of the pulverized overflow product and 50 parts by mass of the crushed wire scrap without adding the master batch. It is a mixture.

  For mixing, weighed overflow pulverized product, electric wire crushed product, and master batch for 3 minutes with a tumbler mixer, and then charged 85 kg of the mixture into a 75-liter batch type kneader. The kneading was completed at a rotation speed of 50 rpm and the resin temperature in the mixer was 180 ° C.

  Next, the kneaded material was put into a 150 mm uniaxial granulation extruder, granulated, and then air-cooled to obtain a regenerated vinyl chloride resin composition.

The conditions of the single screw granulation extruder are
Cylinder: 140-180 ° C., head 180 ° C., screen mesh: 40 + 80 M, air-cooled granulation was performed so that the molded product was 3 mmφ × 3 mmH.

(C) Application evaluation to electric wire materials Each application evaluation of the tensile test, the tensile test after heating, the oil resistance test, the heat deformation test, and the cold resistance test in Table 2 is JISK 6723 (soft polyvinyl chloride compound) type 1 No. 3 ( General sheath) was used as a base.

  In addition, the following items necessary as electric wire materials were added and judged.

Volume resistivity;
Measured by a volume resistivity test specified in 6.8 of JISK6723, and a sample satisfying the standard of volume resistivity (30 ° C.) of 1 × 10 ¹² Ω · cm or more was rated as “good”, and a sample not satisfying it was marked as “poor”.

Hardness shore D;
It measured by the hardness test prescribed | regulated to JISK6301, the thing in hardness Shore D 30-40 was set to (circle), and the others were set to x.

  In consideration of the recycled vinyl chloride resin composition, the heat resistance was evaluated by measuring an aging test, an oil resistance test, heat deformation, cold resistance, and thermal stability.

  Here, the thermal stability is a test method specified in JIS K 6723 6.7, the oil bath temperature is set to 195 ° C., the time until discoloration is measured, and the heat aging test is specified in JIS K 6723 6.4. As measured by a tensile test after heating, the thermal stability was 195 ° C. at 95 MIN or higher (corresponding to a lead-containing product), and the elongation remaining ratio at the time of heat aging was 80% or higher.

Continuous extrudability;
Regarding the continuous extrudability, the occurrence of burns during the 24 hr continuous wire coating operation was observed.

  As a covering material, a CVV3 × 1.25SQ sheath extrusion operation was continuously operated at 90 mmEXT for 24 hours, and then it was visually confirmed whether there was no burn when the head was disassembled, or there were no burn particles on the outer surface of the sheath.

  Extrusion was performed at a cylinder temperature of 130 to 185 ° C, a head of 185 ° C, a die of 185 ° C, and a screen mesh of 40 + 60M.

1 day at 75 ° C water blooming;
A sheet of 25 mm square and 2 mm thickness was immersed in distilled water at 75 ° C., and after one day, it was visually confirmed whether there was any blooming material on the surface.

Comparative Example 1:
This is a recycled product with 50 parts by mass of virgin compound for general sheath, 50 parts by mass of overflow pulverized product, and 50 parts by mass of crushed wire scrap, but the heat aging characteristics after heating, volume resistance, and thermal stability cannot be achieved. It was.

Comparative Example 2:
Overflow pulverized product and electric wire waste pulverized are mixed at 50:50, and are regenerated without adding the masterbatch shown in Table 1. Elongation after heat aging after heating, volume resistance, thermal stability Did not meet the standards.

  Further, in the continuous extrusion work, particles due to burn were generated on the appearance, and the material burned on the sleeve portion after the head was disassembled was confirmed. Lead-free materials are designed to withstand the heat load during extrusion in virgin, but at that time, a hydrochloric acid scavenger is consumed and a by-product (zinc chloride, etc.) is generated. It is presumed that these re-accelerated the dehydrochlorination of the system in the regeneration work with the same thermal history, and lowered the heat stability performance in the high temperature range (180-195 ° C.).

Comparative Examples 3-5:
Comparative Examples 3 to 5 are obtained by adding 5 phr of the master batches a1 to a3 shown in Table 1 with the aim of improving the thermal stability and volume resistance at high temperatures of Comparative Example 1.

  Comparative Example 3 uses a master batch a1 in which the amount of hydrotalcite added is as low as 4 phr, and although heat resistance is improved as compared with Comparative Examples 1 and 2, it is not sufficient.

  Comparative Example 4 uses master batch a2 in which the amount of hydrotalcite added is 54 phr, but the heat resistance is improved, but the volume resistance does not satisfy the standard.

  In Comparative Example 5, the masterbatch a3 having a phenolic antioxidant of 54 phr was used, but white blooming due to the antioxidant occurred and became NG.

  Further, in Comparative Examples 3, 4 and 5, the residual elongation rate in the oil resistance test could not be cleared.

Examples 1-7:
Examples 1-7 use the master batch of a4-a7, and all the characteristics are satisfying the specification value.

  The master batches a4 to a7 have a plasticizer addition amount of 50 phr or more, a hydrotalcite addition amount of 5 to 30 phr, and a phenolic antioxidant addition amount of 3 to 20 phr. It was confirmed that the ratio of addition to 100 parts by mass of the pulverized product was 1 to 10 phr, all satisfying all material characteristics and continuous extrudability, and can be used as a lead-free recycled vinyl chloride resin composition material.

  About the recycled vinyl chloride resin composition of Examples 3 and 4, after extruding it as a coating material for electric wires and examining its characteristics, this was pulverized again, and this was added without adding the PVC masterbatch of the present invention. After re-kneading under the same conditions as in Examples 1 to 7 and applying to the wire covering material seven times, when this was evaluated, all the characteristic items were cleared as in Examples 1 to 7. I found out.

  As a result, the regenerated vinyl chloride resin composition of the present invention requires good thermal stability even after receiving a heat history by kneading and extruding 7 times. It is excellent in recyclability, and once added at the time of recycling, it can be maintained without damaging the characteristics as a recycled vinyl chloride resin composition even if it is regenerated multiple times thereafter. It turned out to be a thing.

From the above, the composition of the masterbatch is
Amount of plasticizer added:
The plasticizer contributes to the improvement of dispersibility when kneading the masterbatch, and if it is small, the dispersibility is bad, and if it is too much, the state becomes excessively slippery and the dispersibility becomes bad. 80 phr is preferred. More preferably, it becomes 50-60 phr. If the amount added is too large, as described above, there will be excessive external lubrication during kneading, and master batch dispersion will be delayed, leading to reduced production efficiency.

Hydrotalcite addition amount:
Hydrotalcite functions as a deoxidation scavenger and exhibits an effect as a deoxidation scavenger, particularly in a high temperature range (around 195 ° C.) during regeneration processing. The addition amount is from 5 to 30 phr, more preferably from 10 to 25 phr, from the viewpoints of heat resistance of the regenerated vinyl chloride resin composition and molding processability during regeneration. If the amount is too large, foaming of the recycled vinyl chloride resin composition is caused, which is not preferable.

Antioxidant addition amount:
The antioxidant has a function of preventing oxidative degradation of the plasticizer, and the addition amount thereof is 3 to 20 phr, more preferably 3 to 15 phr from the viewpoint of preventing the plasticizer from being oxidized. A large addition amount is not preferable because blooming from the surface of the recycled product causes appearance deterioration.

  The amount of the master batch added to the recovered vinyl chloride resin composition is 1 to 10 phr, more preferably 3 to 8 phr, judging from the material characteristics of the raw material overflow pulverized product and wire scrap pulverization. In combination with virgin pellets, it is preferable to determine an appropriate amount range each time.

  As described above, the present invention has been described with reference to an example of an electric wire covering material such as an electric wire coated on a conductor and a cable covered with a plurality of insulated electric wires as an application example of a recycled vinyl chloride resin composition. It is effective in the entire field where free soft PVC is used.

Claims (6)

  In a PVC masterbatch for adding a recovered vinyl chloride resin to obtain a recycled vinyl chloride resin composition, the plasticizer is 50 phr or more, the hydrotalcite is 5 to 30 phr, and the antioxidant is added to the new vinyl chloride resin. A PVC masterbatch for a regenerated vinyl chloride resin composition, containing 3 to 20 phr.   The PVC masterbatch for a regenerated vinyl chloride resin composition according to claim 1, wherein the antioxidant is a phenolic antioxidant.   A recycled vinyl chloride resin composition comprising 1 to 10 phr of the PVC master batch for a recycled vinyl chloride resin composition according to claim 1 or 2 with respect to the recovered vinyl chloride resin.   An electric wire / cable, wherein the recycled vinyl chloride resin composition according to claim 3 is used as a coating material. Adding a plasticizer of 50 phr or more, 5 to 30 phr hydrotalcite, and 3 to 20 phr antioxidant to a new vinyl chloride resin to produce a PVC masterbatch;
A step of producing a recycled vinyl chloride resin composition by melting and kneading the recovered vinyl chloride resin and the PVC master batch;
A method for producing a recycled vinyl chloride resin composition, comprising:   6. The method for producing a regenerated vinyl chloride resin composition according to claim 5, further comprising extrusion-coating the regenerated vinyl chloride resin composition.