JPS5846221B2 - Hard vinyl chloride resin composition - Google Patents

Description

Detailed Description of the Invention The present invention is suitable for index molding products with thin walls and long flow distances, and has excellent melt flowability, low-temperature impact strength, especially low-temperature machining notch eccentricity, thermal stability, and formability. The present invention relates to an excellent hard vinyl chloride resin composition.

In recent years, the replacement of conventional materials such as metal and wood by plastics has been remarkable.

This is because when trying to make various industrial parts such as household appliances and automobile parts using conventional materials such as metal and wood, a large amount of work is required for cutting, cutting, polishing, gluing, assembling, etc. On the other hand, when plastics are used, especially when creative molding is used, a finished product with a complex shape can be obtained in one step.

The main resins used in such index molding include ABS resin, polystyrene resin, and acrylic resin.

On the other hand, polyvinyl chloride resin, which is a resin with excellent chemical resistance, flame retardance, hardness, weather resistance, and surface gloss, is cheap and energy-saving, and although it is consumed in large quantities, it is It is hardly used for other purposes, and only 2-3% is used for special purposes (
It is only used for PVC pipe fittings, telephone sets, etc.).

This is because vinyl chloride resin has a low decomposition temperature (approximately 220
0C), 230 to 30, which is the processing temperature of normal index molding.
The cause is that it cannot be heated to 0°C.

For this reason, the viscosity of the molten resin is high, and the actual situation is that it is not possible to mold the outer shell of a home appliance with a thin wall and a long flow distance due to insufficient flow.

In other words, there is a spiral flow value as a measure of practical fluidity during creation molding, but at a resin temperature of 210°C and a creation pressure of 1000, 9/CI? It is essential for the production of thin-walled, large-sized molded products that the distance flowing through the helical mold maintained at 40 to 50° C. under the condition L is 500 mm or more.

However, it is difficult for polyvinyl chloride resins to satisfy this condition.

Conventionally, in creative molding of vinyl chloride resin, molding is performed at low temperatures and speeds in a high viscosity state, so the overall flow distance within the mold is short and it is only used for limited products with wide gaps. It was nothing more than

Therefore, a dedicated molding machine with various special mechanisms is required, and the products obtained are limited to small products with relatively simple shapes within the thickness range.

As a result of many years of research, the present invention has an aW homopolymerization degree of 30.
0-7501 100 parts by weight of an ethylene-vinyl chloride polymer having an ethylene content of 0.5-15% by weight, b) 25-40% by weight of styrene, 30-60% by weight of butadiene.
, a copolymer 5 to 3 containing 2 to 15% by weight of methyl methacrylate and 0 to 25% by weight of acrylonitrile, and having a torsional rigidity at -60°C of 4 x 10 kg/- or less
5 parts by weight, C) 1.5 to 8 parts by weight of aliphatic carboxylic acid or aliphatic alcohol ester, and d) 2.5 to 10 parts by weight of a basic inorganic lead compound, and R at -20°C.
= 0.01mm notched Izot impact value is 10k
gcm/cr? i or more and 210℃, 1.000
Due to the pressure of creating bait demand, we have completed a hard vinyl chloride resin compound for injection molding for thin-walled and large-sized molded products with a spiral flow value of 500 mm or more.

In recent years, the demand for vinyl chloride resin compositions that can be processed using general-purpose molding machines used for molding ABS1 polystyrene and the like has been increasing rapidly due to flame retardant regulations for home appliance housings and the like.

Therefore, in order to obtain a sufficiently low viscosity below the decomposition temperature,
It is conceivable to extremely reduce the degree of polymerization of vinyl chloride resin or to use copolymerized vinyl chloride resin, but in this case, the mechanical strength of the resulting product would be extremely low, and the softening temperature of the product would decrease, etc. Not practical.

As a method for improving the impact strength of vinyl chloride resin, acrylonitrile-butadiene styrene copolymer (hereinafter abbreviated as ABS) having a rubber component, methyl methacrylate-
A method of mixing reinforcing agents such as butadiene-styrene copolymer (hereinafter abbreviated as MBS) or chlorinated polyethylene, and a method of mixing asbestos or glass fibrous materials are generally known.

In addition, a system in which ABS was added to ethylene-vinyl chloride copolymer was disclosed in JP-A-52-29849, and in JP-A-50-630.
52 is propylene-vinyl chloride copolymer MBS, A
A system with added MBS has been described.

Products created and molded using these conventional vinyl chloride resin compositions have undergone laboratory tests and tests (for example, ASTM
Based on the Izot impact test using D758), it was considered to have a certain level of impact resistance.

However, it has been pointed out that there are problems with low-temperature impact resistance when these conventional vinyl chloride resin compositions are used for housings for home appliances, which are increasingly used in cold regions such as North America in recent years. .

When this phenomenon was investigated, it was found that these conventional vinyl chloride resin compositions have significantly inferior impact resistance compared to ABS when minute scratches or other scratches occur on the surface of the product.

This notch effect is abbreviated as the notch effect.Compared to A, BS, etc. that have conventionally been widely used for these purposes, compositions mainly made of vinyl chloride resins have a notch effect at low temperatures. It is considered to be large and easy to destroy.

In other words, the sharpness of the tip of the test piece in the eye test according to ASTM-D758 is 0.25 mm at the tip, and when this test piece is used, even conventional vinyl chloride resin compositions have no impact value. It can also be made similar to that of ABS.

However, when R is made extremely small, the impact value of conventional vinyl chloride resin compositions suddenly decreases, and AB of the same R is
The reality is that it is a fraction of S.

Therefore, blending a large amount of reinforcing agents such as ABS or MBS with vinyl chloride resin to lower the content of vinyl chloride resin cannot be said to be a substantially vinyl chloride resin composition.
Compositions with reasonable strength have been obtained and used.

For example, in JP-A-54-43256, vinyl chloride resin 1
It is intended to improve conventional vinyl chloride resin compositions by creating a composition consisting of 0 to 60% ABS and 40 to 90% ABS.

Also, in JP-A-54-86546, 70% of vinyl chloride resin was used.
% or less satisfies the impact strength.

However, as a result of this, the melt viscosity of the composition is tensed to that of the reinforcing agent such as ABS and increases significantly.

For this reason, injection molding cannot be performed unless the molding temperature is raised, which inevitably causes thermal deterioration of the composition.

In order to prevent this even to the slightest extent, attempts have been made to use various lubricants, processing aids, etc., but there are still few results that are satisfactory.

For this reason, it is unavoidable that these compositions contain a large amount of organic tin-based stabilizers, which are expensive but have excellent thermal stability.

However, these compositions containing a relatively small amount of vinyl chloride resin component are moving away from the original purpose of using inexpensive and flame-retardant vinyl chloride resin.

Furthermore, such compositions have a unique tackiness due to the use of a large amount of organotin stabilizer, tend to accumulate in the molding machine, and problems associated with thermal decomposition have not always been solved.

The industry has strongly desired the emergence of a flame-retardant indexable molding composition that does not require such expensive and poor molding workability.

However, it was thought that this objective could not be achieved with a vinyl chloride resin composition in which the resin component contains 70% or more of the vinyl chloride resin and only a small amount of reinforcing agent.

However, the present inventors found that a combination system of ethylene-vinyl chloride copolymer resin and MBS copolymer had a unique synergistic effect, and as they proceeded with their investigation, they found that certain fatty acid derivatives and basic inorganic lead compounds By blending into the above system, even though more than 70% of the resin content is vinyl chloride resin, it has extremely excellent melt flowability and low temperature resistant notch effect, and has excellent processability with excellent thermal stability. This led to the invention of a good hard vinyl chloride resin composition.

Using an inorganic lead-based compound, which has an inferior thermal stabilizing effect without using an organic tin stabilizer, which was considered an essential ingredient,
Conventionally, large amounts of fatty acid derivatives have been used, which have been thought to have an adverse effect on thermal stability and cause deterioration such as surface peeling of the resulting product if added in excess of 0.1 to 1.0 parts by weight (based on PVC). However, the excellent performance of this composition must be attributed to the surprising synergistic effect obtained from the coexistence of the above four components.

Basic inorganic lead compounds CD) and aliphatic carboxylic acids (C)
A composite of ethylene vinyl chloride resin and certain MBS
This is thought to be the result of a unique effect on the polymer alloy made of the copolymer [B].

The average degree of polymerization of the vinyl chloride-ethylene copolymer [A] used in the present invention is 300 to 750, preferably 40
0-650 is good.

If the average degree of polymerization is less than 300, the thermal stability will be poor and the mechanical properties of the resulting molded product will deteriorate.

If the average degree of polymerization is 750 or more, sufficient melt fluidity cannot be obtained.

Moreover, the ethylene content in the copolymer needs to be 0.5 to 10% by weight.

If the ethylene content is 0.5% or less, the effects of the present invention cannot be obtained, and if the ethylene content is 10% or more, the heat distortion temperature decreases and sufficient heat resistance cannot be obtained.

Typical monomers that can be copolymerized with ethylene and vinyl chloride include vinyl argaphate, alkyl vinyl ethers, 1,2-ethylenedicarboxylic acid and its derivatives, and acrylic compounds. Inside 1.
The content is 5% by weight or less.

The copolymer (4) mentioned in the present invention can be obtained from commercially available products usually called MBS or AMBS.

MBS or IAMBS is a latex obtained by copolymerizing polybutadiene latex or butadiene with monomers such as styrene, acrylonitrile, methyl methacrylate, etc. It is produced by graft polymerization of monomers, or by polymerization or graft polymerization by other methods, or a blend thereof.

Among these MBS or AMBS, those effective in the present invention include 25 to 40% by weight of styrene and 30 to 6% by weight of butadiene.
0% by weight, 2-15% by weight of methyl methacrylate and 0-25% by weight of acrylonide
Torsional rigidity at 0°C is 4 x 103 to 9/cr
Limited to those that are less than or equal to lt.

Materials outside these limits cannot obtain the desired Izot impact value and spiral claw value, and are disadvantageous for use in thin-walled, large-scale creation molding.

The amount of this copolymer CB') used is 10 parts of the vinyl chloride resin.
It is effective at 5 to 35 parts by weight compared to 0 parts by weight.

If it is less than 5 parts by weight, practically sufficient impact resistance cannot be obtained;
If more than 5 parts by weight is used, the melt fluidity will deteriorate, resulting in poor moldability and the characteristics of the vinyl chloride resin will be lost.

The aliphatic carboxylic acid having 6 to 30 carbon atoms or its ester [C] according to the present invention includes capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, montanic acid, isostearic acid, and hydroxystearic acid. and aliphatic monoalcohol esters and aliphatic polyhydric alcohol esters thereof.

That is, butyl stearate, glyceryl stearate, and the like fall under this category.

The amount of aliphatic carboxylic acid or its ester [C] used is 1.0 to 8 parts by weight, either alone or in combination.

If it is less than 1.0 parts, sufficient melt fluidity and impact resistance cannot be obtained, and if it is more than 8 parts, the compatibility with the resin component is poor and the appearance of the product is significantly deteriorated.

As the basic inorganic lead compound CD) used in the present invention, tribasic lead sulfate, basic lead sulfite, dibasic lead phosphite, basic lead silicate, basic lead carbonate, etc. can be used.

It is characterized in that the amount used is 2 to 10 parts by weight, which is larger than the amount used as a stabilizer for ordinary vinyl chloride resin.

When the amount is less than 2 parts, moldability becomes extremely poor due to resin deterioration and increased tackiness, and the low-temperature notch effect deteriorates, making it easy to break.

If 10 parts or more is added, the impact strength will decrease, which will only worsen economic efficiency and will not provide commensurate benefits. The present invention has the following four precepts [A], [B], [C], and [D]. Although essential, in addition to these, various formulation examples used in ordinary vinyl chloride resin compositions, such as fillers, the above (D
) Other heat stabilizers, antioxidants, weather resistance improvers, pigments, processing aids, lubricants, heat resistance improvers, etc. may be used in combination as long as they do not impair the purpose of the present invention.

In addition, if the R = 0.01 mm notched impact value at -20°C is less than 10 kg/ci, sufficient strength will not be obtained when used in cold regions, and at 210°C, 1000
kg/CI? Spiral flow value at injection pressure of L is 5
If it is less than 0.00 mm, the composition cannot be filled into a mold, and the vinyl chloride composition for injection molding is unsatisfactory for making a predetermined thin-walled, large-sized molded product.

Examples 1 to 23 further illustrate the present invention in Tables 1 and 2.
The present invention will be explained using Comparative Examples 1 to 22, but the present invention is not limited to these Examples.

The various physical properties were measured as follows.

Spiral flow: 21 using Toshiba Machine 15-90B
Creation molding was performed under the conditions of 0°C and 1000 kg/- to determine the flow distance.

Izod impact strength: According to ASTM D256.

In addition, the notch was also made with R=0.01 mm in addition to the R=0.25 specified by JIS, and the reduction rate of the Izod@impact strength value depending on the sharpness of the notch tip was determined.

The reduction rate is the percentage of the impact value at R=0.01 mm divided by the impact value between R=0.25.

Rockwell hardness: Determined on ASTM D758R scale.

UL-94 burning time: Based on the US UL-94 method.

1. Create a test piece with a length of 5 inches, a width of -inch, and a thickness of 1 inch.

Hold the specimen vertically and place a burner flame on its lower end.
Apply the flame for 0 seconds and measure the time from when the flame is removed until the flame is extinguished. Immediately after the flame is extinguished, apply the flame a second time for 10 seconds and measure the time until the flame is extinguished again.

Place cotton under the test piece and observe whether the cotton ignites due to the melted drippings from the test piece.

The above operation was performed on five test pieces, and the total burning time was determined.

Molding method: The compound was blended using a high-speed mixer, then made into pellets using an extruder, and the pellets were molded by creative molding to obtain test pieces.

(Injection conditions: 210℃, injection pressure 1000kg/-1 mold temperature 45℃) Evaluation method: i) Thermal stability during molding: The degree of discoloration and discoloration that appears on the molded product was evaluated on a five-point scale. .

5... No discoloration is observed 4... Discoloration is observed in some spots 3... Discoloration is clearly observed 2... Discoloration is observed throughout ■... Overall 11) Low-temperature impact resistance knee: R = 0 in Izod impact test at 20°C.
．． An impact value between 0.01 and 10.9/- or more was determined as practical strength.

As is clear from the test results of Examples 1 to 12 in Table 1, styrene 25 to 4
0% by weight, 30-60% by weight of butadiene, 2-15% by weight of methyl methacrylate and 0-25% by weight of acrylonitrile.
% by weight and whose torsional rigidity at -60°C is 4X103 kg//d or less [B] is mixed with an aliphatic carboxylic acid having 6 to 30 carbon atoms (C1 and a basic inorganic lead compound [D]). When blended in combination with this, a polyvinyl chloride resin composition with excellent impact resistance due to the low-temperature notch effect and extremely good processing fluidity was obtained.

On the other hand, as is clear from Comparative Examples 1 and 2, when a vinyl chloride homopolymer was used, a composition with a spiral flow of 500 degrees or more could not be obtained even if the same formulation as in Examples 1 to 12 was used. In fact, it has not been possible to obtain large-scale molding with a long flow distance without compromising quality and economy.

Furthermore, as is clear from Comparative Examples 3 to 12, copolymer (5
) is outside the scope of the claims of the present invention, regardless of the amount used, the
A spiral flow value of 0 mm cannot be obtained, and a composition with excellent low-temperature impact strength, thermal stability, flame retardance, hardness, etc. cannot be obtained.

In addition, a box with dimensions of 300 x 800 x 30 and a thickness of 3.2 was made using a Toshiba Machine model 15-630AN extrusion molding machine.
Example 1 with a mold clamping force of 630Ton, an injection temperature of 190°C, a maximum indexing pressure of 1220kg/crlL, and a mold temperature of 45°C.
Molding was performed using the compositions of Comparative Examples 7, 12, and Comparative Examples 1, 3, and 6.

Good products were obtained in all of the Examples, but in the Comparative Examples, no matter which composition was used, only incomplete products were obtained in which the entire mold was not filled with resin.

As is clear from the examples in Table 2, when the copolymer [B] according to the present invention is used as the ethylene-vinyl chloride copolymer, an aliphatic carboxylic acid having 6 to 30 carbon atoms or an aliphatic alcohol ester thereof By blending 1.5 to 8 parts by weight, spiral flow-5007ff71E or higher, R=
With an Izod impact strength of 10 at 0.01 mm, a composition with excellent processability, thermal stability, and flame retardancy can be obtained.

On the other hand, as is clear from Comparative Examples 12 to 16, when the amount of aliphatic carboxylic acids [C] and the basic inorganic lead-based heat stabilizer (D) for vinyl chloride resin is outside the claimed range of the present invention, processing flowability However, it is not possible to obtain a composition that satisfies all of low-temperature impact resistance, flame retardancy, and thermal stability.

As shown in Comparative Examples 17 to 22, even when a similar aliphatic compound outside the scope of this claim is used in place of the aliphatic carboxylic acid or its ester [C], the low-temperature impact resistance (notch effect) passes the test, and processing is possible. A composition with satisfactory fluidity, thermal stability, and flame retardancy cannot be obtained.

Claims (1)

[Scope of Claims] 1 a) The average degree of polymerization is 300 to 750, the ethylene content is 0.5 to 15% by weight, and the vinyl chloride content is 70 to 750.
100 parts by weight of an ethylene-vinyl chloride copolymer IA' consisting of 99.5% by weight and a content of 0.5 to 15% by weight of a monomer copolymerizable with ethylene and vinyl chloride. b) Styrene 25-40% by weight, butadiene 30-60%
% by weight, 2-15% by weight of methyl methacrylate and 0-25% by weight of acrylonitrile, and its -60
15 to 10 parts by weight of a copolymer CB having a torsional rigidity of 4 x 103 kg/- or less at °C. C) 1.5 to 8 parts by weight of aliphatic carboxylic acid or aliphatic alcohol ester having 6 to 30 carbon atoms (C). d) 2.5 to 10 parts by weight of basic inorganic compound (D). A thin wall having an R=0.01-mm notched Izo impact value at -20°C of 10 kg-crIl/cri or more, and a spiral flow value of 500++ m or more at 210°C and an injection pressure of 1000 kg/cr7L; A hard vinyl chloride resin composition for index molding, suitable for large molded products.