JPS5939467B2 - Fire-resistant soft resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fire-resistant soft resin composition.

Fire resistance here refers to flame retardancy, which means that even when heated, it does not melt or flow, retaining its original shape, and when heated, it remains in its original shape and turns black. It refers to the nature.

Moreover, since the composition of the present invention is composed of a soft resin, it is always flexible and resistant to aging.
Fire-resistant soft resin compositions are required in areas such as gray zinc gaskets and electric wire covering materials. Gray zinc gasket is a kind of packing material.
When a glass plate is fitted into a metal sash, it abuts around the glass plate and supports the glass plate within the sash. Gray zinc gasket is a packing material, so it is always flexible and has appropriate mechanical strength.
It must have excellent weather resistance (・) Also, the gray zinc gasket must not deform or flow when it comes into contact with flame. This is because if it flows, it will form slits there, promoting air circulation and increasing the heat of the fire.The same is true for wire sheathing material, if it comes into contact with the flame. If the wire were to flow, the insulation of the wire would be destroyed, creating a danger, so a fire-resistant soft resin composition is required.
However, until now there has been no satisfactory fire-resistant soft resin composition. Up until now, vinyl chloride resin has been used solely as the material constituting gray zinc gaskets. Furthermore, vinyl chloride resins have been exclusively used as coating materials for electric wires. However, if only a vinyl chloride resin was used, it would flow when heated, and the resulting resin would not have good fire resistance. Therefore, the inventor attempted to obtain a soft resin composition with excellent fire resistance.

To this end, the inventor mixed vinyl chloride resins together and further mixed other resins to prepare various resin compositions, and measured the physical properties of the resin compositions. As a result, (a) a graft copolymer resin obtained by graft polymerizing vinyl chloride to ethylene and vinyl acetate, (b) an ordinary vinyl chloride resin, and (c) a copolymer resin of ethylene and vinyl acetate. It has been found that a base material made of a mixture of the following in a specific ratio and a flame retardant, a plasticizer, and an inorganic filler mixed in a normal ratio has good fire resistance. This invention was made based on such knowledge. This invention provides (a) grafting 70 to 40 parts by weight of a monomer containing 90% by weight or more of vinyl chloride to 30 to 60 parts by weight of a copolymer of ethylene and vinyl acetate containing 10 to 45% by weight of vinyl acetate. 100 parts by weight of a graft copolymer resin obtained by polymerization, (b) 50 to 150 parts by weight of a vinyl chloride resin, and (c) a copolymer resin of ethylene and vinyl acetate containing 45 to 70% by weight of vinyl acetate. 3 to 30 parts by weight of a flame retardant and 10 to 100 parts by weight of a flame retardant.
The present invention relates to a fire-resistant soft resin composition containing 10% to 100% by weight of an inorganic filler and 10 to 100% by weight of a plasticizer.

In this invention, a graft polymer resin is used as the first component of the resin mixture. This was obtained by doing so.

There are various grades of copolymers of ethylene and vinyl acetate that serve as the backbone of the graft body. Among these, the copolymer used in the present invention is a copolymer in which vinyl acetate accounts for 10 to 45% by weight, and the remainder is mostly ethylene. The reason why the copolymerization ratio of the core copolymer in the graft body is limited as described above is as follows. In the copolymer, the vinyl acetate component is 4
If the amount exceeds 5% by weight, the obtained graft body will have poor low-temperature flexibility, and therefore the desired resin composition will also have poor low-temperature flexibility. Conversely, the vinyl acetate component is 10
This is because if the amount is less than % by weight, the solubility in the vinyl chloride resin will be poor, and the intended resin composition will therefore have poor mechanical strength. Even if the copolymerization ratio is the same, the quality of the core copolymer will vary depending on the degree of polymerization and the production method, and the graft material may be made from any of these materials.

Among these, it is preferable to use a copolymer obtained by a high-pressure method, and a copolymer with a high degree of polymerization,
That is, it is preferable to use a material with a small melt index. The graft body is made by adding 7 parts by weight of vinyl chloride to 30 to 60 parts by weight of the above-mentioned copolymer of ethylene and vinyl acetate.
It is graft polymerized in a proportion of 0 to 40 parts by weight.

In this case, a part of the vinyl chloride may be replaced with another monomer. That is, the monomer to be graft-polymerized is not limited to vinyl chloride, but vinyl chloride and other monomers may be mixed and graft-polymerized. However, the other monomers must be present in an amount of about 10% or less by weight of vinyl chloride. Other monomers include olefins such as ethylene and propylene, vinyl esters, acrylic esters, methacrylic esters,
Versatric acid esters can be used. The reason why the ratio of the monomer mainly composed of vinyl chloride to the core copolymer is limited as described above is as follows.

If the copolymer is less than 30 parts by weight, the grafted material will have poor flexibility or shape retention during heating;
If the amount exceeds 0 parts by weight, the graft body will have poor mechanical strength. Therefore, the rate of graft polymerization is limited as described above. Graft bodies may differ not only depending on the graft polymerization rate but also on the graft polymerization method. However, the graft polymerization method used in the present invention is not particularly limited. The second component used in the resin mixture is a vinyl chloride resin.

Vinyl chloride resins (hereinafter referred to as vinyl chloride resins) include copolymers of vinyl chloride and other monomers in addition to vinyl chloride homopolymers. Various other monomers can be used, but ethylene is particularly preferred. When using a copolymer with other monomers,
The content of other monomers is limited to 10% by weight or less. As the vinyl chloride homopolymer, commercially available resins, specifically those having a degree of polymerization of 600 to 1,800, particularly those having a degree of polymerization of 800 to 1,400, can be used. The third component blended into the resin mixture is a copolymer resin of ethylene and pinyl acetate (hereinafter referred to as EVA).

As already explained, there are various grades of EVA, but in this invention, one having a vinyl acetate content of 45 to 70% by weight is selected and used. The reason why such a content is selected is that if the vinyl acetate content is 45% by weight or less, the copolymer resin has insufficient compatibility with the graft body and the vinyl chloride resin, and therefore the composition On the other hand, if the vinyl acetate content exceeds 70% by weight, the composition not only lacks low-temperature flexibility but also becomes sticky, which is undesirable. It is from. In this invention, three types of resins are mixed: a graft body, a vinyl chloride resin, and an EVA.

The mixing ratio is 50 to 150 parts of vinyl chloride resin, E
The VA is appropriately determined within the range of 10 to 100 parts depending on the required characteristics. In general, if the amount of PVC resin is small, the flexibility will be good, but the mechanical strength of the resin composition will decrease, and conversely, if the amount of PVC resin is large, the mechanical strength of the resin composition will be lowered. Flammability is improved, but flexibility or fire resistance is reduced. Also, if the amount of EVA is small,
The composition will have poor fire resistance, and conversely, if the amount of EVA used is large, the composition will have improved fire resistance but will have poor mechanical strength. Taking these trends into consideration, a specific mixing ratio will be determined. A flame retardant is incorporated into the resin mixture described above to aid in its flame retardancy. As the flame retardant, it is possible to use most of the flame retardants that are commercially available to be blended into rubber or plastics.Specific examples include brominated polyols, phosphorus-containing polyols, halogen-containing phosphate esters, and halogenated anhydrides. phthalic acid, etc.In addition, plasticizers such as tricresyl phosphate, triphenyl phosphate, and paraffin chloride, as well as antimony oxide and aluminum hydroxide, can also be used as flame retardants. Flame retardants also include what is generally called flame retardant aids.When using flame retardants, it is important to use flame retardants that have good weather resistance for outdoor applications such as gray zinc gaskets. The amount of flame retardant to be blended varies depending on what is specifically used, but is within the range of 3 to 30% of the entire resin mixture. Plasticizers are used to give flexibility.

As the plasticizer, all plasticizers that are generally considered to be usable for polyvinyl chloride can be used. For example, various plasticizers such as phthalic acid-based, phosphoric acid-based, fatty acid-based, epoxy-based, and polyester-based plasticizers can be used. Among these plasticizers, it is preferable to use phosphoric acid-based plasticizers since the object of the present invention is fire resistance. To give a specific example, it is preferable to use tricresyl phosphate, trioctyl phosphate, or the like. The plasticizer is added in a proportion of 10 to 100% based on the total amount of the resin mixture. The reason is that if the plasticizer is less than 10% by weight of the resin mixture, the resulting resin composition will lack flexibility, and if it is more than 100% by weight, the resulting resin composition will be too flexible. This is because mechanical strength decreases and fire resistance becomes poor. In short, the amount of plasticizer is determined appropriately within the above range depending on the resin mixture used and the properties of the plasticizer. In this invention, an inorganic filler is blended into the resin mixture.

As the inorganic filler, it is possible to use almost any material that can be generally incorporated into rubber or plastic. Specific examples include fine powders of calcium oxide, magnesium oxide, calcium hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, calcium silicate, magnesium silicate, and the like. In addition, fine powders such as talc, clay, asbestos, dawsonite, and aluminum hydroxide can also be used. Among these, particularly preferred are calcium or magnesium oxides, hydroxides, carbonates, and silicates. Moreover, aluminum hydroxide is preferable in that it imparts flame retardancy to the graft polymer. All of these materials are used as fine powders as possible. The inorganic filler is added in an amount of 1% to the entire resin mixture.
Blend at a ratio of 0 to 100%. The reason for this is that if the inorganic filler content is less than 10%, the resulting resin composition will have poor heat resistance and shape retention during heating, and conversely, if it is more than 100%, the resulting resin composition This is because things become less flexible. Before blending the inorganic filler into the resin mixture, it is desirable to treat the inorganic filler with stearic acid, a silane coupling agent, a titanium coupling agent, etc. in advance. This is because if the resin composition is pretreated with these materials, the resulting resin composition will be easier to mold, its appearance will be improved, and its mechanical properties will be good. Processing aids may be added to the composition of the present invention in order to improve moldability.

Also, elastomers such as chlorinated polyethylene can be added to improve the elasticity of the composition. In addition, dyes and pigments are added as necessary. The composition of the present invention is prepared by blending the above ingredients in a predetermined proportion, mixing well, and then thoroughly kneading and molding into a desired shape.

In this way, the resin composition of this invention is molded. For molding, machines generally used for processing soft vinyl chloride resin can be used as is. The composition of the present invention has the characteristics of being flexible, having excellent weather resistance, high mechanical strength, and being easy to mold.

In addition, *; (It is flame retardant and does not flow even when heated, it only retains its shape and turns black. Therefore,
The composition of this invention can be formed into a tape and used for covering electric wires or as a packing material.
It is valuable as a fire-resistant covering or packing material. In particular, if this composition is used as a gray zinc gasket, it will improve the fire resistance of buildings, so it has great value as a practical soil. The details of the resin composition according to the present invention will be explained below with reference to Examples.

Examples 1 to 5 As shown in Table 1 below, a graft polymer resin represented by A or B, a vinyl chloride resin represented by C to E, and F
or ethylene-vinyl acetate copolymer resin represented by G in the weight proportions shown in parentheses, and further added with flame retardants, plasticizers, inorganic fillers, and stabilizers in the proportions shown in parentheses. A resin composition was prepared by mixing and kneading thoroughly.

To make a resin composition, the mixture is thoroughly mixed in advance, kneaded with heated rolls, and once formed into a sheet.
This was press-molded to a thickness of 1.5 mm and a width of 12 mm.
A test piece with a length of 120 mm was prepared and subjected to a fire resistance test.

Other physical properties were also measured using this test piece. Also,
A gray zinc channel was molded separately. The test method for fire resistance is to hang the above test piece vertically, bring a flame obtained by burning propane in a Bunsen burner to the lower end for 10 seconds, then release it for 10 seconds, and then touch it for 10 seconds. After this, the flame was removed, and the combustion state of the test piece during this period and shape retention during combustion were examined.

These properties were divided into four levels based on the following evaluation criteria. 1. There is no change in shape - o Dimensional change is 1.
Less than 2 times o
*(2. The shape does not change.

It foams and becomes 1.2 times or more in size. 3. It does not trip, but its shape changes significantly.

4. It trips and completely changes shape.

In addition, practical tests were conducted on the gray zinc channel.

That is, a glass plate with a thickness of 3μ is fitted into the gray zinc channel, fixed to an aluminum sash, and in this state
℃ for 2 hours, and the subsequent shape change was observed. Shape retention was divided into two levels according to the following criteria. It blackens while retaining the L-molded shape, and there is no gap between the aluminum sash and the glass plate.

MDoes not maintain the molded shape.

Due to the flow, the glass plate falls to the bottom of the aluminum sash, creating a gap between the top of the glass plate and the sash. 1st
The results of testing the compositions in the table are shown in Table 2.

From the results in Table 2, it can be seen that the molded articles made from the resin composition of the present invention are flexible and have excellent fire resistance.
It is also found that a more flexible molded article can be obtained by using a copolymer of vinyl chloride with ethylene as the vinyl chloride resin than by using a homopolymer of vinyl chloride. Furthermore, it can be seen that in copolymer resins of ethylene and vinyl acetate, the higher the content of vinyl acetate, the better the fire resistance. Comparative Example 1 In this comparative example, a vinyl chloride homopolymer resin with a degree of polymerization of 1400 was used, and 40 parts of cutyl phthalate and 55 parts of tricresyl phosphate were added to 100 parts by weight of this resin (hereinafter simply referred to as parts and °C). , 60 parts of calcium carbonate, 30 parts of brominated flame retardant, and 3 parts of barium-zinc composite stabilizer used in Example 1 were blended, and this mixture was treated in exactly the same manner as in Example 1 to conduct a fire resistance test. and a practical test.

In the fire resistance test, it was found to be self-extinguishing, but in the 3rd grade, and in the practical test, it was found to be in the M grade.

Claims (1)

[Scope of Claims] 1(a) 30 to 60 parts by weight of a copolymer of ethylene and vinyl acetate containing 10 to 45% by weight of vinyl acetate,
Monomer 70 to 40 containing 90% by weight or more of vinyl chloride
Graft copolymer resin 1 obtained by graft polymerizing parts by weight
00 parts by weight, and (b) 50 to 15 parts of vinyl chloride resin.
0 parts by weight, and (c) 10 to 1 copolymer resin of ethylene and vinyl acetate containing 45 to 70% by weight of vinyl acetate.
00 parts by weight of the resin mixture, 3 parts by weight of the resin mixture
from 10 to 100% by weight flame retardant and from 10 to 100% by weight
A fire-resistant soft resin composition comprising a plasticizer and 10 to 100% by weight of an inorganic filler. 2 Vinyl chloride resin contains ethylene from 2% to 10% by weight
% by weight of a composition according to claim 1.