JPH0418442A - Vinyl chloride-based resin composition excellent in salt water and impact resistance - Google Patents

Abstract

PURPOSE:To obtain a vinyl chloride-based resin composition, capable of maintaining excellent impact resistance even in environment exposed to sea breezes and suitable as protective pipe materials such as various power transmission line materials by blending a vinyl chloride-based resin with specific amounts of a tin laurate-based and/or a tin maleate-based stabilizer and an acrylic rubber. CONSTITUTION:A resin composition is obtained by blending (A) 100 pts.wt. vinyl chloride-based resin (e.g. polyvinyl chloride) with (B) 1-3 pts.wt., preferably 1.5-2.5 pts.wt. tin lauratebased or tin maleate-based stabilizer (e.g. dibutyltin dilaurate) and (C) 3-12 pts.wt., preferably 5-10 pts.wt. acrylic rubber (e.g. ethyl acrylate).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides excellent impact resistance even when applied to places exposed to salt water for long periods, such as various piping materials for bridge installations. Salt water resistant and impact resistant so you can maintain it! The present invention relates to a vinyl chloride resin composition with excellent properties.

[Prior Art] When constructing a bridge, etc., in most cases, various power transmission lines and piping are installed at the bottom or side walls of the bridge. As such power transmission line piping materials, vinyl chloride resin is widely used because it is low cost and suitable for molding long objects. However, power transmission line piping materials are exposed to the atmosphere for long periods of time and are constantly exposed to ultraviolet rays, etc., and those installed on bridges facing the sea are constantly exposed to sea breezes, so they have poor saltwater resistance. Excellent durability is required. Moreover, it is repeatedly subjected to external forces due to vibrations caused by passing cars and trains, etc.
Impact resistance that can withstand repeated external forces is required.

Under these circumstances, in the past, lead-based stabilizing agents and ultraviolet absorbers were added to improve the durability of vinyl chloride-based resins, and MBS-based toughening agents were added to improve impact resistance. A blended vinyl chloride resin composition is used.

However, as mentioned above, vinyl chloride resins containing lead-based stabilizers and MBS-based #i impact strengthening agents deteriorate in a relatively short period of time under the harsh environment of exposure to sea breeze, and their durability deteriorates. Physical properties such as impact resistance deteriorate significantly.

Therefore, various studies were conducted to investigate the causes of such deterioration of physical properties, and the following became clear.

First, lead-based stabilizers, which are most commonly used as stabilizers, generally have poor compatibility or dispersibility with vinyl chloride resins, and when exposed to ultraviolet rays, they can cause chalking (separation from vinyl chloride resins) after being left for a relatively short period of time. This causes a phenomenon in which the powder oozes out onto the surface of the molded product in the form of a powder spray. Correspondingly, the specific surface area of the molded body increases, the elution into the highly ionic salt water is accelerated and the salt is released from the molded body, and its function as a stabilizer is no longer exerted.

In addition, MBS-based impact strengtheners have double bonds in their molecules, making them unstable to ultraviolet rays.Moreover, when salt water is present in the surrounding atmosphere, the following reaction occurs. Molecule fragmentation occurs and impact property modification effects are lost.

1←CH2-CH-CH-CH2→, +2NaC1+2
t(20CI CI [Problems to be Solved by the Invention] The present invention was made with attention to the above-mentioned circumstances, and its purpose is to solve the problem when placed in a harsh environment exposed to sea breeze. However, the present invention aims to provide a vinyl chloride resin composition that can maintain excellent physical properties, particularly impact resistance, for a long period of time.

[Means for Solving the Problems] The composition of the vinyl chloride resin composition according to the present invention that can solve the above problems is such that at least a tin laurate and/or tin maleate stabilizer is added to the vinyl chloride resin. and acrylic rubber, and the preferred blending amount is 1.0 parts by weight of the tin laurate and/or tin maleate stabilizer per 100 parts by weight of the vinyl chloride resin. -3.0 parts by weight, more preferably 15-2.5 parts by weight, and 3-12 parts by weight of acrylic rubber, more preferably 4-10 parts by weight.

[Function] Hereinafter, the reasons for selecting each of the four essential components of the present invention, their functions and effects, preferred blending amounts, etc. will be explained in detail.

Vinyl chloride resin The base resin in the present invention is polyvinyl chloride, but in addition, small amounts of vinyl acetate, vinylidene chloride, acrylic esters, methacrylic esters, styrene, etc. can be copolymerized. A vinyl chloride copolymer copolymerized with a polyvinyl chloride can also be used, and a chlorinated vinyl chloride resin with improved heat resistance etc. by post-chlorination treatment is also preferred. The preferred degree of polymerization of these vinyl chloride resins is appropriately selected depending on the required characteristics of the molded product, but the numerical value is the average degree of polymerization (P
) is in the range of 700 to 1300.

It is well known that vinyl chloride resins undergo a dehydrochlorination reaction when exposed to heat or light, resulting in decomposition and deterioration, and stabilizers are added to suppress such decomposition and deterioration. On the other hand, lead salt stabilizers, which are most commonly used as stabilizers for vinyl chloride resins, have poor compatibility with vinyl chloride resins, as described above, and gradually cause chalking when exposed to ultraviolet rays or the like. Moreover, as mentioned above, when salt water adheres to the surface of the molded product whose specific surface area has been expanded due to the chalking phenomenon, the lead-based stabilizer gradually dissolves and loses its stabilizing effect.

On the other hand, when a tin laurate-based and/or tin maleate-based stabilizer is used as a stabilizer, the above-mentioned severe chalking phenomenon and elution into salt water are less likely to occur, and excellent stability can be maintained for a long period of time. It was confirmed. This is because tin laurate or tin maleate stabilizers have excellent compatibility with vinyl chloride resins, and they themselves not only have excellent weather resistance, but also have low solubility in salt water. This is thought to be due to the fact that these effects are additive or synergistic, increasing the effect of the stabilizer and its sustainability.

Specific examples of tin laurate-based or tin maleate-based stabilizers include tin laurates such as dibutyltin dilaurate, dibutyltin dilaurate, di-2-ethylhexyltin dilaurate, and didecyltin dilaurate; dibutyltin maleate, di-2-ethylhexyltin maleate, dioctyl; Examples include tin maleates such as tin maleate and didecyltin maleate, which can be used alone or in combination of two or more types if necessary.

The preferred amount is 1.0 to 3.0 parts by weight, more preferably 1.5 parts by weight, per 100 parts by weight of the vinyl chloride resin.
-2.5 parts by weight, and if it is less than 1.0 parts by weight, it is difficult to fully exhibit its effect as a stabilizer, whereas if it is added in a large amount exceeding 30 parts by weight, the physical properties of the vinyl chloride resin composition, especially It appears that there is a negative impact on strength.

MBS rubber, which is commonly used as an impact improver for acrylic rubber and vinyl chloride resin, is unstable to ultraviolet rays, and its decomposition is accelerated in the presence of saline, resulting in loss of resistance in a relatively short period of time. As mentioned above, the impact resistance improvement is lost. On the other hand, when acrylic rubber is used as an impact resistance improver, the impact resistance improves!
A vinyl chloride resin composition that maintains high impact resistance for a long period of time can be obtained. This is because there are almost no double bonds in the acrylic rubber molecules, which makes it stable against ultraviolet rays, and also because it does not cause decomposition reactions even in the coexistence of Na'', Cl-, etc. Seem.

In other words, in the present invention, acrylic rubber is a general term for homopolymers or copolymers containing acrylic acid ester as the main monomer component, and includes at least two or more polymerizable double bonds, such as butadiene. Excluded are monomers with

However, when such a monomer is used as a polymerization component, double bonds will remain in the resulting polymer or copolymer, and as in the case of MBS resins, UV rays and saline solution This is because the initial excellent impact improving effect cannot be maintained for a long period of time due to unavoidable decomposition.

Specific examples of acrylic rubber include ethyl acrylate,
Single or copolymer of acrylic ester such as propyl acrylate, butyl acrylate, isopentyl acrylate, or acrylic ester and acrylic acid, 2
-chloroethyl vinyl ether, methyl vinyl ketone,
Examples include copolymers with acrylonitrile and the like, and these can be used alone or in combination of two or more if necessary. The preferred blending amount is 3.0 to 120 parts by weight, more preferably 5.0 to 1040 parts by weight, and 30 to 1040 parts by weight, based on 100 parts by weight of the vinyl chloride resin.
If the amount is less than 12.0 parts by weight, it is difficult to effectively improve the impact resistance, while if it exceeds 12.0 parts by weight, the vinyl chloride resin composition as a whole becomes soft and the bending strength and tensile strength tend to be insufficient.

The essential four components of the present invention are the above three components, or it is of course possible to incorporate various additives as shown below depending on the use and required performance.

It has many functions, such as adjusting the softening temperature of the plasticizer composition, the viscosity during melting, the physical properties of the solidified product, etc., and can be blended in an appropriate amount in the present invention. Specific examples of plasticizers include phthalate esters, dibasic acid esters, phosphoric acid esters, epoxidized vegetable oils, polyester plasticizers, etc. Also, auxiliary plasticizers such as chlorinated paraffin may be used in combination. I have something to do.

It acts as a processing aid that increases the fluidity of the vinyl chloride resin composition when it is melted and improves the slippage with the mold surface.Higher fatty acids such as stearic acid and valmitic acid: or their ethers, Examples include rust conductors such as esters; metal soaps: natural waxes such as carnauba wax and candelilla wax; synthetic waxes such as low polymerization degree polyethylene; paraffin and liquid paraffin.

Fillers are mainly blended as fillers to reduce costs, but depending on the type of filler, it may be expected that it will have a reinforcing filling effect. Specific examples include heavy calcium carbonate, clay, kaolin, silica, carbon black, etc., and reinforcing fibers such as glass fibers, carbon fibers, and metal fibers may also be blended as a type of filler.

Ultraviolet absorber A radical-scavenging compound such as salicylic acid esters, hydroxybenzophenones, and benzotriazoles is used because it absorbs ultraviolet rays and has the effect of suppressing the decomposition of vinyl chloride resins.

Other additives If desired, a small amount of anti-choking agents such as copper-stearic acid, colorants, flame retardants, antistatic agents, blowing agents, anti-fungal agents, etc. may be added.

Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited to the following examples.

[Example] A vinyl chloride resin composition having the component composition shown in Table 1 was prepared, and after roll kneading (185°C) press compression (190°C)
A plate-like product with a thickness of 3 mm was obtained by buffing. A test piece with a length of 100 mm x width of 15+ nm was cut out from this plate, and a JI
A salt spray test was conducted in accordance with S 1 2371 (1961) to examine changes in Charpy impact strength, tensile strength, and elongation over time.

The changes over time in the Charpy impact strength, tensile strength, and elongation of the specimen obtained in Example 1 are shown in Figure 1.2. In the conventional example (comparative example) using the salt water spray, the impact-resistant window strength, tensile strength, and elongation rate all changed rapidly as the salt spray time elapsed, or none of the examples satisfying the requirements of the present invention It can be seen that the degree of change is small, indicating that it has excellent durability against salt spray.

In addition, almost the same tendency was obtained for Example 2.3.

[Effects of the Invention] The present invention is constructed as described above, and by specifying the types of stabilizers and impact resistance improvers, it can be used for a long period of time even under harsh conditions such as exposure to sea breeze. It is now possible to provide a molded article that maintains physical properties such as impact resistance. Therefore, the vinyl chloride resin composition of the present invention can effectively exhibit its characteristics as a protection pipe material for bridge attachment cables and various electric transmission wire materials, and can also be widely used as a material for agricultural piping in coastal areas. I can do it.

[Brief explanation of drawings]

Figure 1.2 compares the performance of the material of the present invention and the conventional material, and is a graph showing changes in impact strength, tensile strength, and elongation rate with the passage of salt spray time. Applicant Ribo Co., Ltd. Figure 1 Salt water spray time (hrs) Salt water spray time (hrs)

Claims (2)

[Claims] (1) A vinyl chloride resin with excellent salt water resistance and impact resistance, characterized by being a vinyl chloride resin blended with at least a tin laurate and/or tin maleate stabilizer and an acrylic rubber. Resin composition. (2) Tin laurate and/or tin maleate stabilizer: 1.0 to 3 parts by weight of vinyl chloride resin.
The vinyl chloride resin composition according to claim 1, wherein 0 parts by weight of acrylic rubber and 3.0 to 12.0 parts by weight of acrylic rubber are blended.