JP2010185056A - Ionomer resin composition, tubular molded product using the composition, and heat shrinkable tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-rigid, flame-retardant material which simultaneously has excellent thin-wall moldability and high rigidity while having flame retardancy, a tubular molded product using the high-rigid, flame-retardant material, and a heat-shrinkable tube using the tubular molded product. <P>SOLUTION: The ionomer resin composition contains a resin (a) containing an ethylenic ionomer resin (A), a flame retardant (b) having a bromine-based flame retardant(B) as a main component, and organoclay (C), a content of the flame retardant (b) being 10-100 pts.wt., and a content of the organoclay (C) being 2-60 pts.wt. based on 100 pts.wt. of the resin (a). An extrusion molded product and the tubular molded product use the ionomer resin composition. The heat-shrinkable tube is obtained using the tubular molded product. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a novel ionomer resin composition, which is a high-rigidity flame-retardant material having both flame retardancy and thin-wall moldability and high rigidity. Furthermore, the present invention relates to a tubular molded product using the ionomer resin composition and a heat shrinkable tube using the tubular molded product.

  Flame retardant tubes (difficulty for electronic parts, OA equipment, consumer electronic equipment such as FPD, DVD, condenser, secondary battery, electronic equipment members, and various parts used in the fields of vehicles, ships, etc. There is a wide demand for flammable tubes. Conventionally, as a flame-retardant tube, an inexpensive and good workability PVC tube has been widely used. However, a flame-retardant tube made of a flame-retardant material that does not use PVC (de-PVC flame-retardant material) is required from the recent trend of de-PVC for environmental measures.

  As a de-PVC flame retardant material, a material obtained by adding a halogen-based flame retardant, an inorganic flame retardant, or the like to a polyolefin-based resin is described in Patent Document 1 (Claim 1), and its use as a tube is also disclosed. ing. For example, Patent Document 1 discloses a flame-retardant polyolefin tube comprising a flame-retardant material obtained by adding a brominated flame retardant / antimony trioxide to a polyolefin resin such as ethylene-vinyl acetate copolymer (EVA). Yes.

  For flame retardant tubes used in various parts such as electronic equipment members and vehicles, another trend is to reduce the thickness of the tubes from the viewpoint of saving space in electronic equipment and reducing vehicle weight. It is getting started. However, the flame retardant tube described above, for example, a tube in which bromine-based flame retardant / antimony trioxide is added to EVA, has poor thin-wall formability (property that enables thin-wall molding processing) even if flame retardancy is obtained. Is difficult. Furthermore, this tube has a problem that its rigidity is low and it is impossible to maintain its shape independently.

  In order to meet the demand for thinning and self-sustaining shape maintenance, a highly rigid tube has been developed, and is disclosed, for example, in Patent Document 2. However, the high-rigidity tube disclosed in Patent Document 2 has no flame retardant added, and although it passes the all tubing test specified by UL224 depending on the tube size, it has higher flame retardancy. It is difficult to pass the VW-1 test.

JP-A-5-138732 JP 2007-204729 A

  The present invention relates to a high-rigidity flame-retardant material having excellent thin-wall moldability and high rigidity while having flame retardancy, a tubular molded product using the high-rigidity flame-retardant material, and the tubular molded product It is an object of the present invention to provide a heat shrinkable tube obtained using the above.

  As a result of earnestly examining the above problems, the present inventors dispersed a flame retardant mainly composed of a brominated flame retardant and an organized clay in an ethylene ionomer resin or a resin containing an ethylene ionomer resin in a predetermined ratio or more. The present inventors have found that the ionomer resin composition can achieve not only flame retardancy but also thin moldability (thin extrusion moldability) and high rigidity, thereby completing the present invention.

  The present inventor, as claim 1, contains a resin a containing an ethylene ionomer resin (A), a flame retardant b containing a brominated flame retardant (B) as a main component, and an organized clay (C). With respect to 100 parts by weight of the resin a, the content of the flame retardant b is 10 parts by weight or more and 100 parts by weight or less, and the content of the organoclay (C) is 2 parts by weight or more and 60 parts by weight or less. An ionomer resin composition is provided.

  The ethylene-based ionomer resin (A) used in the present invention is an intermolecular molecule of an ethylene copolymer having a carboxyl group in a molecule such as an ethylene-methacrylic acid copolymer or an ethylene-acrylic acid copolymer. , A resin that is pseudo-crosslinked with a metal ion such as potassium ion, sodium ion, or magnesium ion, and is disclosed in Patent Document 2, for example. The resin a preferably contains 40% by weight or more of the ethylene ionomer resin (A) in the total amount. Resin a may consist entirely of an ethylene ionomer resin (A).

  The brominated flame retardant (B) refers to a flame retardant containing bromine, such as ethylene bis (pentabromophenyl). The phrase “having the brominated flame retardant (B) as a main component” means that the brominated flame retardant (B) contains 50% by weight or more of the total amount of the flame retardant b. The total amount of the flame retardant b may be a brominated flame retardant (B).

  The organic clay (C) is a layered silicate (clay) such as montmorillonite in which an organic compound is introduced (intercalated) between layers of silicate planes laminated in layers.

  The content of the flame retardant b is 10 parts by weight or more and 100 parts by weight or less with respect to 100 parts by weight of the resin a containing the ethylene ionomer resin (A). If the addition amount is less than 10 parts by weight, flame retardancy cannot be obtained. If the addition amount is more than 100 parts by weight, the effect of improving the rigidity is lowered, and in order to obtain high rigidity, the amount of the organic clay (C) needs to be increased. More preferably, it is 20 to 70 weight part.

  The content of the organized clay (C) is 2 parts by weight or more and 60 parts by weight or less with respect to 100 parts by weight of the resin a containing the ethylene ionomer resin (A). When the content of the organized clay (C) is less than 2 parts by weight, excellent thin-wall formability and high rigidity cannot be obtained. On the other hand, when the content of the organoclay (C) exceeds 60 parts by weight, the productivity is deteriorated such that workability is lowered. More preferably, it is 10 parts by weight or more and 50 parts by weight or less.

  The ionomer resin composition according to claim 1, wherein the ionomer resin composition according to claim 1 contains the resin a, the flame retardant b, and the organized clay (C) in a composition within the above range. It is a high-rigidity flame-retardant material that combines excellent thin formability and high rigidity.

  In the invention of claim 3, the resin a is composed of the ethylene-based ionomer resin (A) and a resin (D) other than the ionomer, and the weight ratio of (A) to (D) is (A) :( D) = The ionomer resin composition according to claim 2, wherein the ionomer resin composition is in a range of 100: 0 to 40:60.

  In the ionomer resin composition of the present invention, the total amount of the resin a may be the ethylene ionomer resin (A), or a part of the ethylene ionomer resin (A) may be replaced with another resin. If the other resin is a resin (D) other than ionomer, and the blending ratio of (A) and (D) is within the range of (A) / (D) = 100: 0 to 40:60, the resin becomes independent. This is preferable because it can be easily melt-kneaded when preparing the ionomer resin composition without deteriorating the thin-wall moldability while maintaining the rigidity capable of maintaining the shape.

  In particular, when antimony trioxide is added to the flame retardant, the resin (D) other than ionomer is added to the resin in the range of (A) / (D) = 95/5 to 65/35 (weight ratio). Is preferred. In other words, it is known that antimony trioxide and the carboxylic acid functional groups of the ionomer are dehydrated by melt kneading to form ionic bonds, but this can be easily achieved by adding a resin other than the ionomer at the above ratio. The reaction can be suppressed. Note that this reaction can also be suppressed by lowering the mixing temperature of the melt-kneading or shortening the heat history.

  In the invention of claim 2, the resin (D) other than the ionomer is a resin selected from an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, a low density polyethylene, a linear low density polyethylene, and a polyester. The ionomer resin composition according to claim 1, wherein the ionomer resin composition is provided.

  Ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, low density polyethylene, linear low density polyethylene, polyester, and the like can be easily blended with ethylene ionomer. Therefore, it is preferably selected as a resin other than the ionomer.

  In the invention of claim 4, the flame retardant b is composed of a brominated flame retardant (B) and antimony trioxide (E), and the weight ratio of (B) to (E) is (B) :( E) = 100. It is in the range of 0-50: 50, The ionomer resin composition according to any one of claims 1 to 3.

  The flame retardant may be entirely brominated flame retardant (B), but a part of it may be replaced with antimony trioxide (E). As described above, it is known that carboxylic acid functional groups of antimony trioxide and ionomer are dehydrated by melt kneading to form an ionic bond. In the prior art, the use of antimony trioxide for ionomer It was difficult. However, in the present invention, as a result of containing the organized clay (C), this reaction was suppressed, and it was possible to add antimony trioxide to the ionomer.

  Further, when the resin D other than the ionomer is blended, the blending of the ionomer / antimony trioxide is further facilitated, which is more preferable from the viewpoint of productivity. Even when a part of the brominated flame retardant (B) is replaced with antimony trioxide (E), the total of (B) and (E) is 10 parts by weight or more with respect to 100 parts by weight of the resin a. 100 parts by weight or less.

  The weight ratio of (B) to (E) is preferably within the range of (B) :( E) = 100: 0 to 50:50. By setting the weight ratio of (B) and (E) within the above range, it is possible to prevent deterioration of the dispersibility of the flame retardant during melt kneading while maintaining flame retardancy, and it is preferable because both properties can be achieved. More preferably, it is the range of (B) :( E) = 90: 10-60: 40.

  The ionomer resin composition of the present invention has excellent extrudability while having flame retardancy. That is, the effect of the present invention is remarkably exhibited when producing an extruded product using the ionomer resin composition of the present invention. Then, as Claim 5, the extrusion molded article formed by extrusion-molding the ionomer resin composition of any one of Claim 1 thru | or 4 is provided. In addition to the tube-shaped molded product described later, examples of the extruded molded product include an electric wire coating, a flat cable, a modified extrusion molded product, a blow molded product, and a film.

  A sixth aspect of the present invention is a tubular molded article obtained by extruding the ionomer resin composition according to any one of the first to fourth aspects into a tubular shape. The ionomer resin composition of the present invention has excellent extrusion moldability, but is particularly excellent in thin-wall moldability. Therefore, the effect of the present invention is particularly remarkable when producing a tubular molded product by extrusion molding.

  The invention according to claim 7 is a heat shrinkable tube characterized in that the tubular molded article according to claim 6 is expanded in the radial direction (expanded diameter) under heating conditions, and its shape is cooled and fixed. .

  A heat-shrinkable tube can be produced by expanding the tubular molded article of the present invention in the radial direction under heating conditions. In the tubular molded product of the present invention, since the ethylene ionomer resin is a base material, the heat-shrinkable tube made from the tubular molded product can be shrunk at a low temperature, and in a device that does not like heat history. Suitable for use in

  According to an eighth aspect of the present invention, the tubular molded article according to the sixth aspect is irradiated with ionizing radiation to crosslink the ionomer resin composition, and then expands in the radial direction under heating conditions, and the shape is cooled and fixed. This is a heat-shrinkable tube.

  It is also possible to produce a heat-shrinkable tube by irradiating the tube-shaped molded product of the present invention with ionizing radiation and then expanding (expanding diameter) in the radial direction under heating conditions. Since this heat-shrinkable tube is also made of an ethylene ionomer resin as a base material, it can be shrunk at a low temperature, and is suitable for use in devices that do not like heat history. In addition, by performing irradiation crosslinking with ionizing radiation, it is possible to satisfy the excellent wear resistance and heat resistance required for heat shrinkable tubes used in wire harnesses for automobile transmissions and the like.

  The ionomer resin composition of the present invention is a high-rigidity flame-retardant material that has excellent thin moldability and high rigidity while having flame retardancy. Since the tubular molded product of the present invention uses this highly rigid flame retardant material, it has both flame retardancy and high rigidity. Since the heat-shrinkable tube of the present invention is obtained using this tubular molded product, it has both flame retardancy and high rigidity, and can be shrunk at a low temperature, and in a device that does not like heat history. Suitable for use.

  Next, the form for implementing this invention is demonstrated. The scope of the present invention is not limited to this embodiment, and various modifications can be made without departing from the spirit of the present invention.

  The ionomer resin composition of the present invention is not only obtained by mixing the resin a, the organic clay (C) and the flame retardant b, but also an ethylene copolymer having a carboxyl group in the molecule and a metal salt, Also included is a resin composition obtained by mixing organic clay (C) and flame retardant b (and other components such as (D) if necessary). When an ethylene copolymer having a carboxyl group and a metal salt are mixed, the carboxyl group is neutralized by a metal ion to become a carboxylate ion, thereby forming a salt with the metal ion. As the plurality of carboxylate ions are associated with metal ions, the ethylene copolymers are pseudo-crosslinked to form an ionomer resin.

  As the ethylene ionomer resin used in the present invention, those commercially available under trade names such as Surlyn and High Milan can be used.

  Examples of the ethylene copolymer having a carboxyl group in the molecule include a copolymer of an acrylic monomer having a carboxyl group such as acrylic acid and methacrylic acid and ethylene, and a copolymer of an acid anhydride monomer such as maleic anhydride and ethylene. Examples are polymers. These copolymers can be produced by a known method such as a copolymerization method or a graft polymerization method, and other monomers can be appropriately copolymerized for the purpose of improving various properties.

  In the ethylene copolymer having a carboxyl group in the molecule, a preferable range of the carboxyl group content is 0.5 to 50 mol%, more preferably 1 to 30 mol%. If it is less than 0.5 mol%, the rigidity and extrusion processability of the resin composition may be reduced, and if it exceeds 50 mol%, the electrolytic solution resistance may be reduced.

  Part or all of the carboxylic acid in the ionomer resin composition is neutralized by metal ions or metal ions in the organized clay. It is preferable that 55% or more of the carboxyl groups in the ionomer resin composition are neutralized because rigidity increases. The neutralization degree of the carboxyl group is the ratio of the amount of ionized carboxyl groups (carboxylate ions) to the total amount of carboxyl groups in the ionomer resin composition. As described in Patent Document 2 and the like, the infrared absorption spectrum ( IR) measurement.

  Examples of the brominated flame retardant (B) include ethylenebis-tetrabromophthalimide (trade name: SAYTEXBT-93, manufactured by Albemarle Corporation), and trade names: SAYTEX402, SAYTEX8010, manufactured by Albemarle Corporation. As the brominated flame retardant (B), a higher bromine content is more effective in imparting flame retardancy. The brominated flame retardant (B) may be appropriately selected and added in consideration of the miscibility with the ethylene ionomer resin to be used or a resin other than the ionomer, but the one not specified in the environmental regulations should be selected. Is preferred.

  The organic clay (C) used in the present invention is a layered silicate (clay) such as montmorillonite in which an organic compound is introduced (intercalated) between the layers of the silicate plane. In layered silicates, intermediate layer cations such as sodium ions and calcium ions exist between layered silicate planes to maintain a layered crystal structure. By exchanging, an organic clay (C) in which the organic compound is chemically bonded to the surface of the silicate plane is obtained.

  In the organic clay (C), the intercalation of the organic compound between the layers increases the interlayer distance between the silicate planes and improves the dispersibility in organic matter. In the case of untreated clay, the interlayer distance does not change in the organic solvent, but the organic clay (C) has the property that the interlayer distance further expands and swells in the organic solvent, so that the dispersibility is further improved. . As such an organized clay (C), those marketed under the trade names such as Nanofil and Sven can be used.

  The layered silicate used as the raw material for the organized clay (C) is generally known as clay or clay, and is a smectite such as montmorillonite, beidellite, hectorite, saponite, stevensite, sauconite, nontronite. In addition to the clay, natural and synthetic clays such as vermiculite, halloysite, and swellable mica, and mixtures thereof can be mentioned.

  Examples of the organic compound used for forming the organoclay (C), that is, the organic compound intercalated between the layers include organic cations composed of quaternary ammonium salts, phosphonium salts, sulfonium salts, and mixtures thereof. . More specifically, examples of quaternary ammonium salts include benzyltrimethylammonium, benzyltriethylammonium, benzyltributylammonium, benzyldimethyldodecylammonium, benzyldimethylstearylammonium, dimethyldistearylammonium, benzyldimethyloctadecylammonium, benzalkonium and the like. Alkyl ammonium ions, alkyl trimethyl ammonium ions such as trimethyl octyl ammonium, trimethyl dodecyl ammonium and trimethyl octadecyl ammonium, dimethyl dialkyl ammonium ions such as dimethyl dioctyl ammonium, dimethyl didodecyl ammonium and dimethyl dioctadecyl ammonium, and trioctyl methyl ammonium Moniumu, trialkyl methyl ammonium ions such as tridodecylmethylammonium include benzethonium ion having two benzene rings.

  As a more specific production method of the organized clay (C), the layered silicate is sufficiently peeled and dispersed in water, and then the organic cation dissolved in water or alcohol is used with respect to the cation exchange capacity of the layered silicate. And a method of ion-exchanging sodium ions and organic cation ions adsorbed on the silicate plane of the layered silicate.

  Resins (D) other than ionomers include polyethylene, polypropylene, ethylene binary and ternary copolymers, graft polymers of these polymers, styrene resins, graft resins of these polymers, and fats. Examples thereof include cyclic polymers, thermoplastic elastomers, plant-derived resins, biodegradable resins, engineering plastics, polyesters, and polyamides.

  As the resin (D) other than the ionomer, a resin having an ethylene moiety or a resin having a high polarity is preferable. An ethylene copolymer, a glycidyl group-containing ternary system, a maleic anhydride-containing ternary system, maleic anhydride-grafted polyethylene, anhydrous Mention may be made of maleic acid graft EVA, polyester-based thermoplastic elastomer, polybutylene succinate, low melting point polybutylene-terephthalate, polybutylene terephthalate, amorphous polyethylene terephthalate, polyethylene and the like.

  More preferred are EVA, ethylene-ethyl acrylate copolymer (EEA), low density polyethylene, linear low density polyethylene (LLDPE), and polyesters. By blending these resins, it is easy to melt and knead the ionomer, and it is possible to suppress an increase in torque and foaming during the melt kneading due to the reaction between antimony trioxide added as a flame retardant and the ionomer resin.

  As the antimony trioxide used in the present invention, a general commercial product can be used.

  In the ionomer resin composition of the present invention, other components, for example, a polyfunctional monomer such as trimethylolpropane trimethacrylate and triallyl isocyanurate, an antioxidant, a flame retardant, Various additives such as an ultraviolet absorber, a light stabilizer, a heat stabilizer, a lubricant, and a colorant can be mixed.

  The ionomer resin composition of the present invention can be produced by melt-kneading the above materials. In melt kneading, mixing can be performed using a known mixing device such as an open roll, a pressure kneader, a single-screw mixer, or a twin-screw mixer, and the mixture is melt-mixed at a temperature equal to or higher than the melting point of the ethylene ionomer resin used. It is preferable.

  The diameter expansion performed when producing the heat-shrinkable tube of the present invention is a method usually performed in the production of a known heat-shrinkable tube, for example, a method of inflating the tube by pressurizing the inside of the tube, and providing the tube with a decompression zone. It can be done by passing through a separate line. The degree of diameter expansion is preferably about 1.5 to 4 times the original inner diameter. Since the tube of the present invention is an ethylene ionomer, the heating temperature during diameter expansion is desirably 60 ° C. or higher and 100 ° C. or lower. However, when the tube-shaped molded article is irradiated with ionizing radiation and the resin is cross-linked, the heat resistance of the tube is improved. Therefore, the temperature is preferably 140 ° C. or higher and 200 ° C. or lower.

  Examples of ionizing radiation sources include accelerating electron beams, gamma rays, X-rays, α rays, ultraviolet rays, etc., but accelerated electrons are used from the viewpoint of industrial use, such as ease of use of ion sources, transmission thickness of ionizing radiation, and speed of crosslinking treatment. Lines are most preferred.

  The acceleration voltage of the accelerating electron beam may be appropriately set depending on the thickness and shape of the molded product. For example, in the case of a molded product having a thickness of 100 μm, the acceleration voltage is selected between 200 and 10,000 kV. An irradiation dose of 30 to 500 kGy provides a sufficient degree of crosslinking.

  The invention will now be described by way of examples. The examples are not intended to limit the scope of the invention.

  First, the production of resin pellets, the production of a tubular molded product, the evaluation of thin-wall formability, the production of a heat-shrinkable tube, and the evaluation of a heat-shrinkable tube performed in the following Examples and Comparative Examples will be described.

(Production of resin pellets)
In the formulation shown in Tables 1 to 5, ethylene ionomer resin (A), brominated flame retardant (B), organic clay (C), resin other than ionomer (D), antimony trioxide (E), and antioxidant Using a twin-screw mixer (26 mmΦ, L / D = 48.5), the material such as the agent is melt-mixed at a barrel temperature of 160 to 180 ° C. and a screw rotation speed of 200 rpm, and then pelletized with a strand cut pelletizer. A pellet of the ionomer resin composition was prepared.

(Production of tube-shaped molded product)
The ionomer resin composition obtained by the production of the above resin pellets is extruded into a tube shape using a single-screw melt extruder (45 mmΦ, L / D = 24), and a tubular molded product having an inner diameter of 10 mmΦ and a wall thickness of 160 μm. (In Tables 1 to 5, it is expressed as 160 μm) and a tubular molded product having an inner diameter of 10 mmΦ and a wall thickness of 80 μm (in Tables 1 to 5, expressed as 80 μm) was obtained. For extrusion, a tubing die having a DDR (Draw Down Ratio) draw rate of 1 to 15 was used, and the extrusion linear velocity was 40 m / min. The DDR withdrawal rate is calculated by the following formula.

DDR withdrawal rate = (D ₁ ² −D ₂ ² ) / (d ₁ ² −d ₂ ² )
(D ₁ : die outer diameter, D ₂ : point outer diameter, d ₁ : coating outer diameter, d ₂ : coating inner diameter)

(Evaluation of thin-wall formability)
Thin-wall moldability was evaluated during the production of the above tubular molded product having a thickness of 80 μm. Thin-wall moldability was determined to be good when 80 μm tubes could be continuously formed, and poor when outer diameter fluctuations, tube breakage, and rough appearance occurred. The evaluation results in each example and comparative example are shown in the row of “formability” in Tables 1 to 5.

(Production of heat-shrinkable tube)
The tube-shaped molded product obtained by the production of the above-mentioned tube-shaped molded product was expanded by heating and then fixed by cooling to obtain a heat-shrinkable tube. In the diameter expansion treatment, the tube-shaped molded product is heated to a temperature equal to or higher than the softening point of the base polymer, and is expanded to a predetermined outer diameter by a method of introducing compressed air into the tube. Performed by fixing.

  In Examples 1 to 10 and Comparative Examples 1 to 5, the tube-shaped molded product was heated to expand the diameter without being irradiated with ionizing radiation. In Examples 11 to 15 and Comparative Examples 6 to 10, the tube-shaped molded product was irradiated with an electron beam of 200 kGy having an acceleration voltage of 2.0 MeV and then expanded under heating. The expanded diameter in the examples and comparative examples was about 2.5 times the original inner diameter. Moreover, in Examples 1-10 and Comparative Examples 1-5, the heating temperature at the time of diameter expansion was 70 degreeC. In Examples 11-15 and Comparative Examples 6-10, since the heat resistance was improved by the treatment with the electron beam, the heating temperature at the time of diameter expansion was set to 140 ° C. or more and 200 ° C. or less.

(Evaluation of heat shrinkable tube: shrinkage temperature)
The heat-shrinkable tube obtained by the production of the heat-shrinkable tube is left in a gear oven at 50 ° C. for 3 minutes to measure the tube inner diameter. Thereafter, the temperature was raised by 10 ° C. and left for 3 minutes, the inner diameter (A) was measured, and the shrinkage rate (%) was determined by the following formula. The temperature at which the shrinkage rate reached 80% or more was defined as the shrinkage temperature. The results in each example and comparative example are shown in the row of “shrinkage temperature” in Tables 1 to 5.

Shrinkage rate (%) = 100 × (1− (A−B) / (C−B))
A: Inner diameter after heating (mm)
B: Inside diameter of extruded tube (mm)
C: Inside diameter of the extruded tube after expansion (mm)

(Evaluation of heat-shrinkable tube: rigidity test)
The heat-shrinkable tube obtained by the production of the heat-shrinkable tube was cut into a length of 100 mm, and one end was supported so that the tube was horizontal. At this time, in the tube having low rigidity, the mouth of the other end that is not supported may be closed or the tube may hang down without being kept horizontal, but this case was determined to be unacceptable. The case where it was not such a shape and the tube was self-standing with the mouth open (maintaining horizontal) was determined to be acceptable. The evaluation results in each example and comparative example are shown in the row of “rigidity test” in Tables 1 to 5.

(Evaluation of heat-shrinkable tube: elastic modulus)
The heat-shrinkable tube was cut to a length of 10 cm, a tensile test was performed at a tensile speed = 100 mm / min, and a distance between marked lines = 20 mm, and an elastic modulus (MPa) was obtained from a stress-elongation curve. The evaluation results in each example and comparative example are shown in the row of “elastic modulus” in Tables 1 to 5.

(Evaluation of heat-shrinkable tube: flame retardant test)
The VW-1 vertical combustion test described in UL standard 224 was performed on five samples. In the test, when each sample was ignited 15 seconds for 5 times, the fire extinguished within 60 seconds, the absorbent cotton laid on the bottom was not burned by burning fallen objects, the kraft paper attached to the top of the sample burned Those that did not burn were considered acceptable levels, and all 5 points reached acceptable levels as “accepted”. If one of the 5 points did not reach the pass level, it was judged as “Fail”. The evaluation results in each example and comparative example are shown in the “flame retardant test” row in Tables 1-5.

Next, materials used in the following examples and comparative examples are shown below.
1. Ethylene ionomer resin (A): Trade name Himiran 1706 (Mitsui DuPont Polychemical Co., Ltd., MFR = 0.9) (shown as “ionomer” in the table)
2. Resins other than ionomer (D):
An ethylene-vinyl acetate copolymer having a vinyl acetate content of 46% by weight and MFR = 2.5 (shown as “EVA1” in the table).
An ethylene-vinyl acetate copolymer having a vinyl acetate content of 15% by weight and MFR = 1.5 (shown as “EVA2” in the table).
An ethylene ethyl acrylate copolymer having an ethyl acrylate content of 23% by weight and MFR = 0.5 (shown as “EEA” in the table)
LLDPE with MFR = 0.6 (shown as “LLDPE” in the table)
3. Brominated flame retardant (B):
Ethylene bis (pentabromophenyl) (melting point 350 ° C., bromine content 82%) (trade name: Saytex 8010)
4). Organized clay (C):
Product name: Nanofil 15 (a product using dimethyl distearyl ammonium salt as an interlayer organic treatment agent) manufactured by ROCK WOOD
5). Antimony trioxide (E): product with an average particle size of 1 μm Antioxidant: Hindered amine stabilizer (trade name: Nowguard 445, manufactured by Crompton)

[Examples 1 to 3]
An ethylene ionomer resin (A), a brominated flame retardant (B), an organized clay (C), and an antioxidant are blended according to the formulation shown in Table 1, and the above-mentioned “preparation of resin pellets” (barrel Resin pellets were prepared according to a temperature of 180 ° C., and then tube-shaped molded products having a thickness of 80 μm and 160 μm were prepared according to the method of “Production of tube-shaped molded product”. In addition, the moldability was evaluated according to “Evaluation of thin-wall moldability”. Furthermore, using the obtained tube-shaped molded product, a heat shrinkable tube was produced according to the method in the case of performing no irradiation with ionizing radiation in “Preparation of heat shrinkable tube”, and regarding its shrinkability, rigidity, elastic modulus, and flame retardancy Evaluation was carried out by the above-mentioned “Evaluation of heat-shrinkable tube”. The results are shown in Table 1.

  From the results shown in Table 1, Examples 1 to 3 can be interpreted as good in terms of moldability, shrinkage temperature (if less than 110 ° C., good), rigidity test, and elastic modulus (if 300 MPa or higher). )), It was confirmed that all results of the flame retardant test showed good results.

[Example 4]
Preparation and evaluation of a tubular molded product and a heat-shrinkable tube were carried out in the same manner as in Example 1 except that antimony trioxide (E) was added and the barrel temperature at the time of resin pellet production was 160 ° C. The results are shown in Table 1. From the results shown in Table 1, it was confirmed that Example 4 showed good results in all evaluations of moldability, shrinkage temperature, rigidity test, elastic modulus, and flame retardancy test.

[Examples 5 to 10]
In Examples 5 to 6 and 8 to 10, except that the resin (D) other than the ionomer was added in the type and formulation shown in Table 1 or Table 2, the same as in Example 4, a tubular molded product, heat A shrinkable tube was prepared and evaluated. Moreover, in Example 7, resin (D) other than ionomer was added according to the formulation shown in Table 2, and the addition amount of brominated flame retardant (B) and antimony trioxide (E) was changed. In the same manner as in Example 4, evaluation was performed using a tubular molded product and a heat-shrinkable tube. The results are shown in Table 1 or Table 2. From the results shown in Table 1 or Table 2, it was confirmed that Examples 5 to 10 showed good results in all evaluations of moldability, shrinkage temperature, rigidity test, elastic modulus, and flame retardancy test.

  In addition, when the ratio of resin (D) other than ionomer is increased, a decrease in elastic modulus is observed (comparison between Examples 4 to 6), but both have passed the rigidity test and have independent rigidity. . Moreover, between Examples 5-10, although the kind and ratio of resin (D) other than an ionomer are changed, the significant difference is not looked at by the evaluation result, and it is melt-kneading with ethylene-type ionomer resin. It is considered that there is no particular problem as long as the resin can be blended.

[Comparative Example 1]
A tube-shaped molded product and a heat-shrinkable tube were prepared and evaluated in the same manner as in Example 2 except that the brominated flame retardant (B) was not added. The results are shown in Table 3. In Comparative Example 1, the flame retardant test was not passed because no flame retardant was added.

[Comparative Example 2]
A tube-shaped molded product and a heat-shrinkable tube were prepared and evaluated in the same manner as in Example 1 except that the organic clay (C) was not added. The results are shown in Table 3. In Comparative Example 2, since the organoclay (C) was not added, the flame retardancy test was passed, but the thin-wall processability deteriorated, and a tube having a wall thickness of 80 μm could not be stably formed. Further, the elastic modulus was low even with a tube having a wall thickness of 160 μm.

[Comparative Example 3]
A tube-shaped molded product and a heat-shrinkable tube were produced and evaluated in the same manner as in Example 4 except that the organic clay (C) was not added. The results are shown in Table 3. In Comparative Example 3, since the organoclay (C) was not added, the flame retardancy test was passed, but the thin-wall processability deteriorated, and a tube having a thickness of 80 μm could not be stably formed. Further, the elastic modulus was low even with a tube having a wall thickness of 160 μm.

[Comparative Example 4]
Except that the ratio (weight ratio) of ethylene ionomer resin (A) / resin (D) other than ionomer was 30/70, in the same manner as in Example 5, a tube-shaped molded product, production of a heat-shrinkable tube, Evaluation was performed. The results are shown in Table 3. In Comparative Example 4, since the ratio of ethylene ionomer was low, a tube having a wall thickness of 80 μm could be produced, but the wall thickness was not stable and the workability was low. In addition, the elastic modulus is greatly reduced, and the self-supporting rigidity cannot be obtained.

[Comparative Example 5]
Except for using EVA1 which is a resin (D) other than an ionomer instead of using an ethylene ionomer resin (A), a tubular molded product, production of a heat-shrinkable tube, as in Example 4, Evaluation was performed. The results are shown in Table 3. In Comparative Example 5, since the ethylene ionomer resin (A) was not used, the extrusion moldability and rigidity were low.

[Example 11]
An ethylene ionomer resin (A), a brominated flame retardant (B), an organized clay (C), and an antioxidant are blended according to the formulation shown in Table 4, and the above-mentioned “preparation of resin pellets” (barrel Resin pellets were prepared according to a temperature of 180 ° C., and then tube-shaped molded products having a thickness of 80 μm and 160 μm were prepared according to the method of “Production of tube-shaped molded product”. In addition, the moldability was evaluated according to “Evaluation of thin-wall moldability”. Further, the obtained tube-shaped product is irradiated with 200 kGy of ionizing radiation having an acceleration voltage of 2.0 MeV, and a heat-shrinkable tube is produced according to the method of “Preparation of heat-shrinkable tube”. Evaluation was made on the flammability by the method of “Evaluation of heat-shrinkable tube”. The results are shown in Table 4. From the results shown in Table 4, it was confirmed that Example 11 showed good results in all evaluations of moldability, shrinkage temperature, rigidity test, elastic modulus, and flame retardancy test.

[Example 12]
Preparation and evaluation of a tubular molded product and a heat-shrinkable tube were carried out in the same manner as in Example 11 except that antimony trioxide (E) was added and the barrel temperature at the time of resin pellet production was 160 ° C. The results are shown in Table 4. From the results shown in Table 4, it was confirmed that Example 12 showed good results in all evaluations of moldability, shrinkage temperature, rigidity test, elastic modulus, and flame retardancy test.

[Examples 13 to 15]
In Examples 13 to 15, a tube-shaped molded product and a heat-shrinkable tube were prepared and evaluated in the same manner as in Example 12 except that the resin (D) other than the ionomer was added in the type and formulation shown in Table 4. Carried out. The results are shown in Table 4. From the results shown in Table 4, it was confirmed that Examples 13 to 15 showed good results in all evaluations of moldability, shrinkage temperature, rigidity test, elastic modulus, and flame retardancy test.

  In addition, between Examples 13-15, although the kind and ratio of resin (D) other than an ionomer were changed, the significant difference was not looked at by the evaluation result, and ethylene-type ionomer resin and melt-kneading were carried out. It is considered that there is no particular problem as long as it is a resin that can be blended with.

[Comparative Example 6]
Preparation and evaluation of a tubular molded product and a heat-shrinkable tube were performed in the same manner as in Example 11 except that the brominated flame retardant (B) was not added and the addition amount of the organic clay (C) was 60 parts by weight. Carried out. The results are shown in Table 5. In Comparative Example 6, the flame retardant test was not passed because no flame retardant was added.

[Comparative Example 7]
In the same manner as in Example 11 except that the organic clay (C) was not added and the addition amount of the brominated flame retardant (B) was 30 parts by weight, the tube-shaped molded product and the heat-shrinkable tube were produced and evaluated. Carried out. The results are shown in Table 5. In Comparative Example 7, since the organic clay (C) was not added, the flame retardancy test was passed, but the thin-wall processability was deteriorated, and a tube having a thickness of 80 μm could not be stably formed. Further, the elastic modulus was low even with a tube having a wall thickness of 160 μm.

[Comparative Example 8]
A tube-shaped molded product and a heat-shrinkable tube were prepared and evaluated in the same manner as in Example 12 except that the organic clay (C) was not added. The results are shown in Table 5. In Comparative Example 8, since the organoclay (C) was not added, the flame retardancy test was passed, but the thin-wall processability deteriorated, and a tube having a wall thickness of 80 μm could not be stably formed. Further, the elastic modulus was low even with a tube having a wall thickness of 160 μm.

[Comparative Example 9]
Except that the ratio (weight ratio) of ethylene ionomer resin (A) / resin (D) other than ionomer was 30/70, in the same manner as in Example 13, a tubular molded product, production of a heat-shrinkable tube, Evaluation was performed. The results are shown in Table 5. In Comparative Example 9, since the ratio of the ethylene ionomer was low, a tube having a wall thickness of 80 μm could be produced, but the wall thickness was not stable and the moldability was low. In addition, the elastic modulus is greatly reduced, and the self-supporting rigidity cannot be obtained.

[Comparative Example 10]
Except for using EVA1 which is a resin (D) other than ionomer instead of using ethylene ionomer resin (A), a tube-shaped molded product, production of a heat-shrinkable tube, as in Example 12, Evaluation was performed. The results are shown in Table 5. In Comparative Example 10, since the ethylene ionomer resin (A) was not used, the extrusion moldability and rigidity were low.

Claims (8)

  A resin a containing an ethylene ionomer resin (A), a flame retardant b mainly composed of a brominated flame retardant (B), and an organized clay (C), and 100 parts by weight of the resin a, The content of the flame retardant b is 10 parts by weight or more and 100 parts by weight or less, and the content of the organic clay (C) is 2 parts by weight or more and 60 parts by weight or less. .   The resin (D) other than the ionomer is a resin selected from an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, a low density polyethylene, a linear low density polyethylene, and a polyester. Item 12. The ionomer resin composition according to Item 1.   The resin a containing the ethylene ionomer resin (A) is composed of the ethylene ionomer resin (A) and a resin (D) other than the ionomer, and the weight ratio of (A) to (D) is (A) :( The ionomer resin composition according to claim 2, wherein D) is in the range of 100: 0 to 40:60.   The flame retardant b mainly composed of the brominated flame retardant (B) is composed of the brominated flame retardant (B) and antimony trioxide (E), and the weight ratio of (B) to (E) is (B): The ionomer resin composition according to any one of claims 1 to 3, wherein (E) is in a range of 100: 0 to 50:50.   An extrusion-molded product obtained by extrusion-molding the ionomer resin composition according to any one of claims 1 to 4.   A tube-shaped molded product obtained by extruding the ionomer resin composition according to any one of claims 1 to 4 into a tube shape.   A heat-shrinkable tube obtained by expanding the tubular molded product according to claim 6 in a radial direction under heating conditions and cooling and fixing the shape.   The tube-shaped molded article according to claim 6 is irradiated with ionizing radiation to crosslink the ionomer resin composition, and then expands in a radial direction under heating conditions, and the shape is cooled and fixed. Shrink tube.