JPH0250137B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vinyl chloride resin composition having good processability. Although polyvinyl chloride resin has good chemical and physical properties and is widely used, it has the drawback of poor processability in various ways. In other words, the melt viscosity is high and the fluidity is poor, the processing temperature is close to the thermal decomposition temperature, so the forming processing area is narrow, and the gelation rate is slow, so it is difficult to quickly and uniformly transform the powder from a powder into a molten product by roll kneading operations, etc. , the surface condition of the melt-molded product often becomes poor. It is well known that the addition of plasticizers solves some of these drawbacks, but in addition to problems such as plasticizer volatilization and escape, it also causes a decrease in mechanical properties, making it difficult to fully utilize rigid polyvinyl chloride. This is far from a solution. On the other hand, by increasing the gelation rate of the resin during molding processing of vinyl chloride resin and reducing the adhesion to the metal surface of the molding machine, productivity can be improved and the surface of the molded product can be smoothed, allowing for a long time. With the aim of improving processability, such as giving the molded product a gloss that does not change even when continuously molded, preventing so-called drawdown during blow bottle molding, and improving fluidity in large injection molding machines, we have developed vinyl chloride resin and Although several compatible copolymers have been investigated as processing aids and have achieved great success in some applications, the main ones currently in use on the market are methyl methacrylate-based copolymers. It is a polymer. PVC resin mixed with these has a large effect of accelerating the gelation rate and has a large improvement in secondary processability, such as an increase in tensile elongation at high temperatures, but on the other hand, the gloss of extruded film is It also has drawbacks that reduce the commercial value of molded products, such as defects and the occurrence of ungelled substances (also called gelatinized eyes). In addition, since the above-mentioned methyl methacrylate copolymer inherently has high adhesiveness to metal surfaces and high melt viscosity, it is difficult to mold a vinyl chloride resin composition to which a copolymer containing methyl methacrylate as a main component is added. A productivity-related drawback has been found in that sometimes the torque (kneading resistance) increases significantly. The use of various lubricants in combination is being considered in order to improve these drawbacks, but there is an upper limit to the amount used in order to maintain the physical properties of the vinyl chloride resin composition, and even within this range, it is difficult to maintain lubricity. This method cannot be a general solution because it has additional drawbacks such as lack of stability, blooming on the surface of the molded product, and adhesion of lubricant to the mold during processing and molding (also called plate-out). not present. As a composition that solves the above problems all at once,
In other words, it maintains the transparency of vinyl chloride resin, improves processability such as drawdown, improves fluidity during molding, improves elongation at high temperatures, and releasability from the roll surface during calendering. Compositions with extremely long-lasting lubricity properties have also been devised, and have been highly effective. There is a need for processing aids with good properties and long-lasting lubricity.
The above compositions have limitations. Furthermore, depending on the formulation, an increase in deposits on molds, etc. (plate-out) may be observed during molding, and it cannot be said that market demands are fully satisfied. Taking the above points into consideration, the present inventors conducted extensive studies and found that while having the excellent processability of the polymethyl methacrylate, it also has excellent fluidity and long-lasting lubricity. Furthermore, we succeeded in obtaining a composition free from the plate-out phenomenon, and arrived at the present invention. The present invention comprises () 99.95 to 90 parts by weight of a polyvinyl chloride polymer and/or copolymer of which at least 80% by weight is vinyl chloride; () 5 to 100% by weight of (A) methyl methacrylate; For a solution of 0.1 g of polymer in 100 ml of chloroform obtained by polymerizing a monomer or monomer mixture consisting of 95-0% by weight of possible monomers:
In the presence of 5 to 45 parts by weight of a non-rubber-like polymer or copolymer having a reduced viscosity (ηsp/C) of 2 or less as measured at 25°C, (B) acrylic whose alkyl group has 1 to 18 carbon atoms. 40 to 70% monomer or monomer mixture consisting of 100 to 30% by weight of alkyl acid and 70 to 0% by weight of alkyl methacrylate whose alkyl group has 1 to 18 carbon atoms
Part by weight is polymerized under conditions such that ηsp/C of the polymer of component (B) becomes 1 or less, and in the presence of the obtained polymer containing both components (A) and (B), ) 50-100% by weight of methyl methacrylate and monomers copolymerizable with it
A three-stage polymer obtained by polymerizing 5 to 40 parts by weight of a monomer or monomer mixture consisting of 50 to 0% by weight.
It is a vinyl chloride resin composition with good processability, consisting of 0.05 to 10 parts by weight, and has excellent processability and long-lasting lubricity while maintaining the processability improvement effect of polymethyl methacrylate. Moreover, the present invention provides a new transparent vinyl chloride resin composition that does not cause bleed or plate-out during molding. The feature of the present invention is that, in component (), a low molecular weight acrylic ester polymer or a copolymer of acrylic ester and methacrylic ester (component (B)), which affects so-called lubricity, is used. Inside and outside of this component, vinyl chloride resin is a relatively small molecular weight resin with good compatibility.
The purpose is to form a so-called Sanderch structure in which the methacrylate polymer (A) and (C) components are arranged.
This sandwich structure is made of a polymer containing at least 5% methyl methacrylate, and methacrylic acid Mixture of ester and acrylic ester or acrylic ester (component (B)) to ηsp/ of the polymer of component (B)
Addition polymerization is carried out under conditions such that C becomes 1.0 or less,
Then, in the presence of this latex, as component (C),
It can be easily obtained by addition polymerization of methyl methacrylate or a mixture containing 50% or less of a monomer component copolymerizable with methyl methacrylate, especially by applying a three-stage emulsion polymerization method. In order to form this sandwich structure, in the second and subsequent stages of polymerization, the polymerization is carried out without adding any additional emulsifier, and the formation of a polymer consisting of components (B) and (C) alone is substantially prevented. It is preferable to keep it to a minimum. Since polymethyl methacrylate with a high degree of polymerization has a high softening temperature, it is not sufficiently dispersed under normal vinyl chloride resin processing conditions, leaving a large amount of ungelled material. Furthermore, if the processing conditions are strengthened for dispersion and the processing is continued until the ungelled matter is eliminated, the ungelled matter will disappear by kneading with the vinyl chloride resin, but it will be unsuitable for practical use due to thermal deterioration. For this purpose, the methyl methacrylate component (A) with good dispersibility and low ηsp/C is used as the core, and the surrounding material (B) has a large slipping effect.
The composition of the present invention is obtained by blending a composition obtained by polymerizing the components extremely densely and then polymerizing a methyl methacrylate monomer having good compatibility with the vinyl chloride resin on the outside of the polymer with the vinyl chloride resin. Not only does it have an excellent effect on improving the processability of vinyl chloride resin, but component (B) also contains methacrylic acid ester, which has good compatibility with vinyl chloride resin, resulting in the occurrence of bleed and plate-out. It has the excellent property of solving difficult problems during molding and not impairing the transparency of vinyl chloride resin. Moreover, although the methacrylic acid ester contained in component (B) is thought to have a high adhesion to metal surfaces, it does not impede the sustainability of processability and lubricity, but rather improves processability and lubricity. It also has the surprising effect of increasing sustainability, and the following effects cannot be achieved with conventional known compositions. For example, if styrene, which has poor compatibility with vinyl chloride resin, is added to component (B), which is the content of the sandwich structure, bleed, plate-out, etc. will easily occur, and the amount of deposits on the mold etc. will increase during the molding process. Moreover, there is a limit to the long-term sustainability of the slipperiness. The present invention provides a composition that has excellent lubricity and processability due to the Sanderutsch structure obtained by a three-stage polymerization method and the mutual effect of each component, especially component (B), methacrylic ester and acrylic ester. death,
With such a composition and structure, a desired composition can be obtained. This sandwich structure composition is
These are extremely important requirements for the processability and lubricity of vinyl chloride resin, releasability from metal surfaces, bleeding on metal surfaces, and eliminating plate-out.
Even if component (B) and component (C) are used alone, or (A)
Even if the monomers used for components (B) and (C) are simultaneously polymerized in one step, excellent lubricity cannot be obtained. In addition, the polymer consisting of component (B) is used as a core, and the component (A) or
A two-layer structure with a polymer consisting of component (C) (e.g.
Component (B) is first polymerized, and then (A) is polymerized in the presence of component (B).
Even in the case of two-stage polymerization (obtained by two-stage polymerization of components), unlike the Sanderch structure, the mold releasability from the metal surface and the long-term sustainability of lubricity are inferior. Furthermore, if component (C) is not present, component (A) is the core, and component (B) is the outer layer, component (B) has a low Tg and is blocked during the coagulation and drying process, making it difficult to convert into vinyl chloride resin. It is difficult to obtain it industrially as a powder that can be dispersed. The amount of component (A) in 100 parts by weight of the three-stage polymer used in the composition of the present invention is 5 to 45 parts, preferably 20 to 40 parts. If it exceeds 45 parts, the lubricity will be impaired, and if it is less than 5 parts. In this case, the processability is impaired and the durability of the lubricity is also deteriorated. One of the characteristics of the present invention is that the molecular weight of component (A) is small, and the molecular weight such that ηsp/C is at least 2 or less indicates excellent dispersibility with the vinyl chloride resin. It is also necessary to maintain processability and lubricity. Even if it exceeds 2, sustained lubricity can be obtained, but the dispersibility in the vinyl chloride resin is lowered and fish eyes are more likely to occur. Component (A) is polymethyl methacrylate or a copolymer containing 5% by weight or more of methyl methacrylate, but there is no particular restriction on the partner monomer for copolymerization of methyl methacrylate, and an appropriate monomer may be used depending on the final purpose. You can use your body. For example, one or more of aromatic vinyl, unsaturated nitriles, vinyl esters, acrylic esters, methacrylic esters other than methyl methacrylate, etc. are used, but the amount used is 95%.
Exceeding this is not preferable because the features of the present invention will be impaired. Furthermore, it is also possible to use polyfunctional monomers such as divinylbenzene and allyl methacrylate as component (A), but in this case, the amount used is preferably 2.0% or less. The content of component (B) in 100 parts by weight of the three-stage polymer is 40~
70 parts, preferably 50-60 parts. If it is less than 40 parts, the lubricity will be impaired, and if it exceeds 70 parts, the surface properties (gloss) will be impaired.The major feature of component (B) is to keep the molecular weight extremely low; It is necessary for ηsp/C to be 1.0 or less in order to obtain excellent sustainability of slipperiness, and preferably ηsp/C
is around 0.5. When ηsp/C exceeds 1.0, the lubricant effect is impaired, and ultimately the three-stage polymer no longer exhibits excellent lubricity. Among the monomers constituting component (B), methacrylic acid ester accounts for 70 to 0% by weight, and acrylic acid ester accounts for 100 to 30% by weight. If the content of acrylic ester exceeds 70%, the gelation behavior of the final product will be delayed, but the effect on lubricity such as mold releasability from metal surfaces and fluidity will be good. However, if it is less than 30%, the lubricity effect becomes extremely poor. Examples of the acrylic ester used in component (B) include ethyl acrylate, butyl acrylate,
Isobutyl acrylate, 2-ethylhexyl acrylate, etc. can be used. As the methacrylic ester, for example, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, etc. can be used. Both acrylic ester and methacrylic ester have a glass transition temperature. The effect is great when monomers that give a low polymer content, such as butyl acrylate, 2-ethylhexyl acrylate, butyl methacrylate, 2-ethylhexyl methacrylate, etc. are used. In addition, in order to achieve this result, it is necessary for the methacrylic ester and acrylic ester in component (B) to take the form of random copolymerization, such as grafting an acrylic ester to a methacrylic ester, Or, it is not preferable to have the binding mode reversed. That is, if a bond such as butyl acrylate is present in the product as a block, the composition obtained by mixing the final product with a vinyl chloride resin will lose its transparency. The content of component (C) in 100 parts by weight of the three-stage polymer is 5~
There are 40 copies. If it is less than 5 parts, excellent workability cannot be fully exhibited, and secondary agglomeration is likely to occur in post-processes such as coagulation, dehydration, and drying, resulting in problems in terms of productivity. Moreover, if it exceeds 40 parts, the long-term sustainability of the slippery property will be lost. Component (C) can contain a monomer copolymerizable with methyl methacrylate in an amount of 50% or less, but methyl methacrylate alone is preferred in order to effectively impart excellent final processability. In addition, even if the ηsp/C of component (C) is not particularly regulated, it will not impair the good workability and sustained slipperiness that are the characteristics of the present invention, but when emphasis is placed on workability such as drawdown prevention effect. is more than 2,
Further, when emphasis is placed on dispersibility and fisheye etc. are to be avoided, it is preferable to set the number to 2 or less. Even in this case, polymethyl methacrylate with a high degree of polymerization has a high softening temperature, so it does not have sufficient dispersibility under the processing conditions of vinyl chloride resin, leaving a large amount of ungelled material. , generation must be suppressed as much as possible. The synthesis of the three-stage polymer is preferably carried out by emulsion polymerization, and the emulsifier used therein may be any commonly known emulsifier, and the polymerization initiator may be a water-soluble, oil-soluble single system or redox system. It will be done. Also, the polymer ηsp/
C can be arbitrarily adjusted using common methods such as chain transfer agents and polymerization temperature. The method of mixing the three-stage polymer () synthesized in the above manner with the vinyl chloride resin () is not particularly limited and may be carried out in accordance with a commonly used method. Stabilizers, lubricants, plasticizers, impact-strengthening agents, colorants, fillers, foaming agents, and the like can be added to the obtained vinyl chloride resin composition, if necessary.
In the following examples, parts indicate parts by weight. Example 1 280 parts of ion-exchanged water and sodium dioctyl sulfosuccinate were placed in a reaction vessel equipped with a stirrer and a reflux condenser.
A mixture of 1.5 parts of ammonium persulfate, 2.0 parts of ammonium persulfate, 30 parts of methyl methacrylate as component (A), and 0.05 parts of n-octyl mercaptan was charged, and after purging the inside of the container with nitrogen, the temperature of the reaction container was raised to 65°C while stirring. hand,
The mixture was heated and stirred for 2 hours. Next, a mixture of component (B), 25 parts of n-butyl methacrylate, 25 parts of n-butyl acrylate, and 0.5 parts of n-octyl mercaptan, was added dropwise over 1 hour, and after the addition was completed, 2 more parts of n-butyl methacrylate were added.
Stir for hours. Thereafter, a mixture of 20 parts of methyl methacrylate and 0.03 parts of n-octyl mercaptan as component (C) was added to the reaction system over 30 minutes.
The mixture was further stirred for 2 hours to complete the polymerization. The obtained emulsion was cooled, then salted out using aluminum chloride, filtered, washed and dried to produce a polymer. Comparative Example 1 In the reaction vessel used in Example 1, 280% ion-exchanged water was added.
1.5 parts of sodium dioctyl sulfosuccinate, 20 parts of ammonium persulfate, 25 parts of component (B) butyl methacrylate, 25 parts of butyl acrylate, and 0.5 parts of n-octyl mercaptan. The reaction vessel was heated to 65°C and stirred for 2 hours. Subsequently, a mixture of 50 parts of methyl methacrylate and 0.08 parts of n-octyl mercaptan as component (C) was added over 30 minutes, and the polymerization was completed by further stirring for 2 hours. was manufactured. Comparative Example 2 Component (C) in Comparative Example 1 was used as component (A) in this comparative example, component (B) was added and polymerized, and a polymer was produced in the same manner as in Example 1. Comparative Example 3 In a reaction vessel, 280 parts of ion-exchanged water, 1.5 parts of sodium dioctyl sulfosuccinate, and ammonium persulfate were added.
2.0 parts, 50 parts of methyl methacrylate, 25 parts of n-butyl methacrylate, 25 parts of butyl acrylate,
After charging 1.2 parts of n-octyl mercaptan and purging the inside of the container with nitrogen, the temperature of the reaction container was raised to 65°C under stirring, and the polymerization was completed by heating and stirring for 2 hours.
Thereafter, a polymer was produced in the same manner as in Example 1. Appropriate amounts of the polymers in each of the above examples were mixed with 100 parts of polyvinyl chloride resin (average degree of polymerization -700), dibutyltin mercapto.
Table 1 summarizes the processability measurement results of a vinyl chloride resin composition obtained by mixing 2.0 parts of vinyl chloride, 1.0 parts of epoxy auxiliary, 0.5 parts of dibutyltin malate, and 0.3 parts of lubricant in a Henschel mixer. Ta. Note that Comparative Example 4 was evaluated without adding any polymer. As is clear from Table 1, Comparative Example 3, in which all the components were polymerized in one step, showed no slippery effect at all, and Comparative Example 2, in which the two-stage polymerization consisted of component (A) and component (B), Compared to the present invention, the lubricity is significantly inferior, some ungelled substances are observed, and the transparency is also inferior. Comparative example 1 is
Although there is some roll slippage, the sustained slippage (stickiness) is significantly inferior to that of the composition of the present invention, and moreover, ungelled substances are observed. In contrast, the examples of the present invention are superior in all aspects. The measurement conditions in the table are as follows. 1 Roll slipperiness: using 6-inch rolls, roll kneading temperature 200°C x 195°C, roll spacing 1mm, sample
After 5 minutes of kneading with 100 g, the peelability from the roll surface was compared. The evaluation is on a 5-point scale, with 5 being the highest peeling and 1 being the lowest peeling, and the closer the value is to 5, the greater the slipperiness. Note that phr is the number of parts of the polymer relative to 100 parts of polyvinyl chloride. 2 Stiffness: Same as the formulation used for roll slipperiness, roll mixing temperature 205℃ x 200℃, interval 1
mm, 100 g of sample is kneaded (however, the amount of polymer added is 1.0 phr based on the vinyl chloride resin), and the time required for the sheet to stick to the roll surface and not peel off is measured. The longer this time, the better the durability of slipperiness at high temperatures. 3 Ungelled material; Plate out: The same formulation as that used for roll slippage, the amount of polymer added was 20 phr of vinyl chloride resin, and the sample was heated at 180°C
Knead at 175℃ for 5 minutes to create a 0.3mm sheet.
The presence or absence of ungelled material was determined. At that time, plate-out was determined based on the presence or absence of deposits on the roll surface. Plate out is determined under the same conditions as above.
The test was also carried out in the case of kneading for 10 minutes. 4. Transparency: Using a sample with the same formulation as used for roll slippage, with the amount of polymer added being 20 phr for vinyl chloride resin, the sample was kneaded for 5 minutes and then press-pressed at 185°C, and pressed to a thickness of 2 mm. After creating the plate, it was measured using an integrating sphere haze meter (according to JIS-6714). 5 Blow bottle moldability: 20 parts of dibutyltin mercapto in 100 parts of vinyl chloride resin (average degree of polymerization 720)
part, dibutyltin malate polymer 0.5 part, lubricant
A sample containing 1.0 part of the polymer of each example was extruded using a blow molding machine (40 mmφ), and the weight of the balisong was measured at 5 seconds to determine flowability, the length was measured, and the drawdown property and thickness were measured. The swell behavior is measured by measuring the swell behavior, and a sample that does not contain polymers is used as the standard.
Comprehensively superior to the blank ◎ Blank 〇 Inferior to the blank △ Very inferior ×

[Table] Examples 2 to 5, Comparative Examples 5 to 6 Under the same conditions as in Example 1, except that the monomer component (A) was changed to 30 parts of methyl methacrylate, and the monomer component (B) was changed to 25 parts of ethyl methacrylate. , 25 parts of butyl acrylate, 20 parts of methyl methacrylate as the monomer component (C), and ηsp/C of each component as n
- Polymers of Examples 2 to 5 and Comparative Examples 5 to 6 having various ηsp/C as shown in Table 2 were prepared by adjusting the amount of octyl mercaptan, and Example 1
Each vinyl chloride resin composition was prepared using the same formulation as above, and its processability was measured. The results are shown in Table 2.
As is clear from Table 2, ηsp/C of component (B) is 1.0
In the above cases, as well as poor lubricity, ungelled materials are observed, but the examples of the present invention are superior in all aspects of processability compared to these comparative examples.

[Table] Examples 6 to 10, Comparative Example 7 Same manufacturing conditions as Example 1, except for Example 6.
In Example 7, the monomer of component (B) was 50 parts of butyl acrylate, and the monomer of component (B) was ethyl methacrylate.
35 parts, butyl acrylate 15 parts, and Example 8
The (A) component monomers were 10 parts of methyl methacrylate and 20 parts of ethyl methacrylate, and in Example 9, the (A) component monomers were the same as in Example 8, and the (C) component was 10 parts of methyl methacrylate and 10 parts of ethyl methacrylate. In Example 10, the monomers of component (B) were 35 parts of ethyl methacrylate and 30 parts of butyl acrylate, and in Comparative Example 7, the monomer of component (B) was ethyl methacrylate.
45 parts of vinyl chloride and 5 parts of butyl acrylate, respectively, and prepared each vinyl chloride resin composition using the same formulation as in Example 1. The processability of the resin composition was measured, and the results are shown in Table 3. As is clear from Table 3 (B)
If the butyl acrylate content of the component is less than 30% by weight, the slipperiness will be poor. All workability is excellent within the range of the examples of the present invention.

【table】

Claims (1)

[Claims] 1 () A polyvinyl chloride polymer and/or copolymer in which at least 80% by weight is vinyl chloride
99.95-90 parts by weight and ()(A) 5-100% by weight of methyl methacrylate,
0.1 in 100 ml of chloroform, obtained by polymerizing a monomer or monomer mixture consisting of it and 95 to 0% by weight of a copolymerizable monomer.
In the presence of 5 to 45 parts by weight of a non-rubber-like polymer or copolymer having a reduced viscosity (ηsp/c) of 2 or less as measured at 25°C, (B) alkyl A monomer or monomer mixture consisting of 100 to 30% by weight of alkyl acrylate whose group has 1 to 18 carbon atoms and 70 to 0% by weight of alkyl methacrylate whose alkyl group has 1 to 18 carbon atoms.
40 to 70 parts by weight of the polymer of component (B)
is 1 or less, and in the presence of a polymer containing both components (A) and (B), (C) 50 to 100% by weight of methyl methacrylate,
5 to 40% monomer or monomer mixture consisting of 50 to 0% by weight of a monomer copolymerizable with it
A vinyl chloride resin with good processability, consisting of 0.05 to 10 parts by weight of a three-stage polymer obtained by polymerizing parts by weight (the sum of components (A), (B), and (C) is 100 parts by weight). Composition.