JPS6358857B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vinyl chloride resin composition for powder molding, and more particularly, the present invention relates to a composition that provides a coating film with good fluidity and low frictional resistance. Generally, when a synthetic resin composition for powder molding is to be used for processing by the fluidized dipping method, the composition itself is required to have good powder flowability, and the following processing properties are also required: is required. These processing properties include good melt flowability, uniform adhesion thickness, no sagging, no discoloration at high temperatures, and low frictional resistance of the coating film. For a vinyl chloride resin composition for fluidized dipping (hereinafter sometimes referred to as a vinyl chloride resin composition), 25 to 100 parts by weight of vinyl chloride resin (hereinafter referred to as a vinyl chloride resin) in the composition is a necessary component.
Parts by weight (hereinafter, such expressions will be expressed as PHR)
A plasticizer is added. Among these, a blending amount of around 40 PHR is often used, but even in such a case, excellent powder flowability cannot necessarily be obtained. In order to improve powder flowability, it is effective to reduce the amount of plasticizer blended to 20.10 PHR. However, in these cases, the melting temperature of the PVC resin composition is high, so in addition to the melt fluidity of the composition, the physical properties of the coating of the molded product obtained by the fluidized dipping method using the composition, such as gloss, are The properties and thickness uniformity become poor. As a second method for obtaining excellent powder fluidity, a method has been proposed in which the vinyl chloride resin particles constituting the vinyl chloride resin composition are coated with certain fine particles. However, certain fine particles that have been proposed, such as emulsion polymerized products of vinyl chloride, have an average particle size of about 1 μm, which is too large for this coating purpose, so it is difficult to achieve a sufficient coating. It requires a lot of focus. If a fluidized bed is formed using a PVC resin composition containing a large amount of such a coating material, not only will the coating material particles scatter and contaminate the working environment, but also the coating material particles will move up and down within the fluidized bed. It is classified into Therefore, the PVC resin coating formed on the surface of the workpiece processed by the fluidized dipping method in such a fluidized bed lacks uniformity in thickness. This drawback is particularly noticeable in the vertical uniformity of the coating thickness when coating a so-called long object such as a long pipe by the fluidized dipping method. A method has also been proposed in which a fine powder of an inorganic substance having an average particle size of about 1 μm is used as the certain fine particles.
However, this method also requires a large amount for the same reason as mentioned above, and since the fine powder generally does not melt at the gelation temperature of the PVC resin composition, the melt viscosity of the composition increases, and the fine powder in the melt increases. There is a problem that it is difficult to uniformly disperse the In addition, coated molded products produced by the fluidized dipping method using this composition have the disadvantage that the film is poor in smoothness and gloss, and is therefore impractical. In order to improve the high frictional resistance of the coating film obtained by the fluidized dipping method, which is another drawback of PVC resin compositions, it is possible to add certain ingredients to the PVC resin composition in advance and allow it to bleed after molding. Methods of reducing frictional resistance on the surface of molded articles are known.
Such additives include various plasticizer stabilizers and lubricants. However, these have drawbacks such as stickiness or decreased gloss when they bleed onto the surface of the molded product. As a result of our earnest efforts to solve these technical problems related to improving the powder fluidity of PVC resin compositions for fluidized dipping, the present inventors have discovered that an inorganic or organic material with a particle size of 10 to 100 mμ is used as certain fine particles. We realized that the above technical problem can be solved by Furthermore, the inventors have found that the problem of reducing the frictional resistance of molded articles can be solved by adding a small amount of silicone oil to the PVC resin composition without causing stickiness or reducing gloss as described above. The present invention was completed based on the above two findings. As is clear from the above description, the object of the present invention is to provide a vinyl chloride resin composition for fluidized dipping that has good powder flowability and good coating film properties of molded products obtained when used in the fluidized dipping method. It is on offer. Other objectives will become apparent from the description below. The present invention includes: (1) 100 parts by weight of vinyl chloride resin powder, 25 to 25 parts by weight of a plasticizer;
A vinyl chloride resin composition for fluidized dipping, which contains 100 parts by weight, 0.01 to 0.5 parts by weight of fine powder of an inorganic or organic substance having a particle size of 10 to 100 mμ, and 0.01 to 0.3 parts by weight of silicone oil. (2) PVC resin powder and plasticizer at a temperature of 80° to 130°
After mixing at ℃ and the plasticizer is completely absorbed into the vinyl chloride resin powder, a fine powder of an inorganic or organic substance with a particle size of 10 to 100 mμ is mixed, and silicone oil is mixed with the vinyl chloride resin powder and the plasticizer. A method for producing a vinyl chloride resin composition for powder molding, which comprises mixing before, during or after mixing. It is. The configuration and effects of the present invention will be explained in detail below. B. The vinyl chloride resin powder used in the present invention is not only a homopolymer of vinyl chloride, but also a copolymer of vinyl chloride and other copolymerizable monomers, with a vinyl chloride content of 50% by weight or more. Alternatively, it refers to a powdery mixture of a vinyl chloride homopolymer or a copolymer of vinyl chloride and other monomers and other thermoplastic synthetic resins, with a vinyl chloride portion of 50% by weight or more. Other monomers include, but are not limited to, vinylidene halides such as vinylidene chloride, vinyl esters such as vinyl acetate, acrylic acid, acrylic esters such as acrylonitrile or methyl acrylate, and ethylene or propylene. Examples include α-olefins. The particle size of the vinyl chloride resin powder is not particularly limited, but usually 40 to 300 mesh, preferably 80 to 200 mesh is easy to use. (b) The plasticizer used in the present invention may be any plasticizer that can be used for vinyl chloride resin, such as phthalate esters such as dioctyl phthalate and dibutyl phthalate, and adipic acid esters such as dioctyl adipate and dibutyl adipate. , phosphoric acid esters such as tricresyl phosphate, and higher alcohol esters of long-chain fatty acids such as oleic acid and sebacic acid. The amount of such plasticizer used is 25 to 100 PHR, preferably 25 to 100 PHR, based on the aforementioned vinyl chloride resin powder.
~50PHR. If it is less than 25 PHR, the melt fluidity described below will deteriorate, and if this deterioration is compensated for by an increase in the temperature of the fluidized product, the PVC resin will be thermally degraded, and the mechanical and thermal properties of the resulting resin film will deteriorate. Moreover, if it exceeds 100 PHR, not only will the powder fluidity described below deteriorate, but also the PVC resin constituting the PVC resin composition will aggregate during flow. (c) Inorganic or organic substance with a particle size of 10 to 100 mμ used in the present invention; Any material can be used as the fine powder as long as it can be blended into the vinyl chloride resin composition for fluidized dipping. However, if there is no known technology for industrially producing ultrafine powder of 10 to 100 mμ, it is virtually impossible to use it. Examples of usable fine powders of inorganic substances include aluminum oxide, magnesium oxide, barium carbonate, and silicic anhydride. Further, the method or timing of adding and mixing the above-mentioned fine powder used in the present invention to other composition raw materials of the present invention is not limited, but the following five methods can be considered, for example. In other words, add it by dispersing it in a plasticizer, add it by dispersing it in a vinyl chloride resin powder, put the vinyl chloride resin powder and plasticizer in a mixer, mix and raise the temperature (from room temperature).
80° to 130°C), added at the end of the mixing, i.e. after the vinyl chloride resin powder has absorbed the plasticizer, and added after the absorption (80° to 130°C).
This method is such as adding it during cooling. In the second invention (method invention) of the present invention, the above method is used. The reason is as follows. In other words, if the above method is adopted, the particle size in the composition raw materials being mixed is 10 to 100.
Since the fine powder of an inorganic or organic substance of mμ absorbs the plasticizer itself, it becomes very difficult for the fine powder to uniformly coat the surface of the vinyl chloride resin powder. On the other hand, in the above case, that is, when the plasticizer is added after being absorbed into the vinyl chloride resin powder, an appropriate amount of the plasticizer remains on the surface of the powder, so that inorganic substances with a particle size of 10 to 100 mμ or The fine organic substance powder adheres firmly to the surface of the vinyl chloride resin powder. Then, even when this vinyl chloride resin composition is subsequently used for processing by a fluidized dipping method, the vinyl chloride resin powder and the fine powder are not separated and classified. Therefore, the powder fluidity during the processing can be greatly improved. D. Silicone oil used in the present invention; Although the silicone oil is not limited,
Mention may be made, for example, of dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane and methylhydrogenpolysiloxane. The amount used is 0.01 to 0.3 PHR based on the vinyl chloride resin used. Less than 0.01PHR has no effect, 0.3PHR
There is no particular increase in effectiveness even if used in excess of this amount. In addition, in the second invention of the present invention, the mixing temperature of the vinyl chloride resin powder and the plasticizer and the mixing temperature of the fine powder of an inorganic substance or organic substance with a particle size of 10 to 100 mμ after mixing are set to 80° to 130°. It must be ℃. If the temperature is lower than 80°C, the amount of plasticizer acidified on the surface of the vinyl chloride resin powder is too large, making it difficult to disperse the fine powder and uniformly adhere it to the vinyl chloride resin powder. Also, 130
If the temperature exceeds ○A, the amount of plasticizer remaining on the surface of the resin powder will be too small, and the adhesion of the fine powder to the resin powder will be reduced, making it easier to classify the resulting composition when it is fluidized. Become. Furthermore, part of the resin powder (○) melts and aggregates to form large particles, and the width of the particle size distribution of the resin powder deviates from the optimum width. It becomes necessary to separate and remove the components, resulting in a decrease in the yield of the composition. For the above reasons, the temperature range is more preferably 90° to 125°C, which is suitable when a large amount of plasticizer is added, such as 50 to 100 PHR. Furthermore, the difference from the above embodiment of the present invention is that in the former, fine powder of inorganic or organic material with a particle size of 10 to 100 mμ is mixed while maintaining the temperature in an arbitrary temperature range of 80° to 130°C. In the latter case, the fine powder can be mixed while the material to be mixed is still between 80° and 130° C. during the cooling start period before the end of mixing, and the latter method saves time. The mixing time for the fine powder is not limited, but 1 minute to 60 minutes, usually 3 minutes to 20 minutes, is sufficient depending on the performance of the mixer used. F. The method or timing of adding the silicone oil used in the second invention of the present invention is not limited;
It may be done before, during or after mixing the PVC resin powder and the plasticizer. Before mixing is 80
It refers to the case where the PVC resin powder or plasticizer is mixed in advance at a temperature below ℃.During mixing refers to the state where the PVC resin powder and plasticizer are mixed at a temperature of 80℃ to 130℃.After mixing refers to After mixing the PVC resin powder and plasticizer at 80° to 130°C (note: the absorption of the plasticizer into the resin must reach a certain limit), add a fine powder of inorganic or organic material of a certain particle size to the mixture. A state in which they can be mixed. Further, silicone oil can be added while the PVC resin composition continues to cool down to less than 80°C or room temperature after the mixing, but it is possible to uniformly disperse the silicone oil and to add PVC resin particles (gelled). (including) tends to be insufficiently absorbed. Ultimately, a preferred embodiment is before, after, or at the same time as the addition of the fine powder such as inorganic substance after mixing, and addition at this time is most effective for improving the powder fluidity of the PVC resin composition of the present invention. Effective. The present invention will be explained below with reference to Examples. Examples 1-4, Comparative Examples 1-2 20 kg of vinyl chloride resin with an average degree of polymerization of 710, plasticizer
Mix 8 kg of DOP and 1 kg of tin-based stabilizer in a Henschel mixer with a capacity of 100 for 25 minutes while heating at 100°C.
Predetermined amounts of calcium carbonate and silicone oil (dimethylpolysiloxane) listed in Table 1 below were added and cooled to produce a vinyl chloride resin composition (hereinafter sometimes referred to as a compound). Then,
20 kg of this compound was flowed in a tube with an inner diameter of 290 mm, and the floating rate and flow state (fluidity) were observed. This compound was then used in a fluidized dipping method to evaluate melt flowability during coating film formation, followed by gloss, thickness uniformity, and bleedability after coating film formation using the following six-step method. That is, a steel pipe with an outer diameter of 50 mm and a length of 400 mm is placed in the fluidized bed of the compound in the pipe in advance.
The steel pipe was heated for 10 minutes in an electric furnace at 310°, immersed for 5 seconds, then pulled out and allowed to cool to form a vinyl chloride resin coating on the surface of the steel pipe. In addition, regarding the mass resistance and strength test, a 100 mm x 300 mm iron plate was similarly heated, immersed for 5 seconds, pulled up, and left to cool. Measured by machine. Incidentally, this matusa resistance was also evaluated using the following six-step method in the same manner as the fluidity etc. described above. The results are shown in Table 1 below.

【table】

[Table] As is clear from the table above, when the amount of calcium carbonate, which is an ultrafine particle, is increased while other conditions are the same, powder fluidity and thickness uniformity improve, but
It is clear that the melt flowability and glossiness deteriorate. From the above results, the amount of calcium carbonate used is
Within the range of 0.01 to 0.5 PHR, a powder molding vinyl chloride resin with good coating film properties including fluidity and mass resistance can be obtained. Examples 5 to 8, Comparative Examples 3 and 4 The same procedure as Example 1 was carried out except that the amounts of calcium carbonate and silicone oil added were changed. The amounts added and the results are shown in Table 2.

[Table] As is clear from the table above, the influence of the amount of silicone oil used on various physical properties can be divided into the following three groups. A group of physical properties that show good results regardless of the amount of silicone oil added; powder fluidity, melt fluidity, and thickness uniformity. (b) A group whose physical properties deteriorate when a large amount of silicone oil is added; glossiness (not possible at 0.5PHR) and bleedability (especially not possible at 0.5PHR). (c) Physical properties that cannot be achieved without the addition of silicone oil; mass resistance. From the above results, the amount of silicone oil added is 0.01
~0.3PHR is desirable. Examples 9 to 12, Comparative Examples 5 and 6 Same as Example 1 except that the amounts of calcium carbonate (0.1 PHR) and silicone oil (0.1 PHR) were constant and the amount of plasticizer (DOP) used was varied. carried out. Table 3 shows the amount of plasticizer blended and the results.

[Table] As is clear from the table above, the influence of the amount of plasticizer used on various physical properties can be divided into the following two groups. B. A group that shows good physical properties regardless of the amount of plasticizer added; melt fluidity (excluding 15PHR) and mass resistance. (b) Physical property groups that deteriorate when too much plasticizer is added: Powder fluidity, thickness uniformity (excluding 15PHR)
and bleedability. C. Physical properties that deteriorate if the amount of plasticizer added is too small or too large; glossiness. From the above results, the range of usable plasticizers is 25
~100 PHR, preferably 25-50 PHR. Furthermore, from the results in Table 1, the amount of fine particles with a particle size of 10 to 100 mμ is preferably 0.01 to 0.5 PHR, and from the results in Table 2, the amount of silicone oil used is 0.01 to 0.5 PHR.
0.3PHR is desirable. Further, the ratio of the amount of fine particles having a particle size of 10 to 100 mμ and silicone oil used is not particularly limited, and each may be added within the above range depending on the degree to which improvement in fluidity and stiffness resistance is required. Examples 13 and 14, Comparative Examples 7 to 9 The same procedure as in Example 1 was carried out except that the timing of addition of calcium carbonate (0.1 PHR) and silicone oil (0.1 PHR) was changed. Regarding addition timing and results, 4th
Shown in the table.

[Table] Note: For details on how and when to add calcium carbonate and silicone oil,
Do the following.
B. Dispersion in plasticizer: Add the blended amount of calcium carbonate and silicone oil to the plasticizer to be used, stir well and mix. (b) Simultaneous addition with PVC resin: After adding about half of the amount of PVC resin mixed into the mixer, add calcium carbonate, then add the remaining PVC resin, make it into a sandwich sandwich, and add silicone oil while stirring and mixing. C. During temperature rise: Put the PVC resin, plasticizer, and other raw materials into a mixer, and while mixing, heat the raw material mixture with water vapor, etc. through the mixer to raise the temperature (80 to 130℃),
Before the PVC resin absorbs all the plasticizer, add a predetermined amount of calcium carbonate and silicone oil and mix uniformly. D. After absorbing the plasticizer; carry out in the same manner as C. above, but
After the plasticizer is sufficiently absorbed into the PVC resin, predetermined amounts of calcium carbonate and silicone oil are added and mixed uniformly. E. During cooling: carry out the same procedure as above (D), but after a certain aging period from the heated state (80 to 130°C), add the specified amount of calcium carbonate and silicone oil and mix uniformly. do. As is clear from the table above, the powder fluidity of PVC resin is affected by the timing of addition of calcium carbonate, etc., and becomes impossible or poor if it is "dispersed in a plasticizer" or "added at the same time as PVC resin". . This is because, in the case of this addition method, ultrafine powders such as calcium carbonate are absorbed into the particles of porous PVC resin powder, and the adhesion on the powder surface, which directly contributes to maintaining fluidity, is greatly reduced. It is presumed that this is because of this. On the other hand, melt flowability, glossiness, bleedability, etc. other than powder flowability are not affected by the above-mentioned addition timing. This problem occurs after the PVC resin is plasticized and melted, so it is understood that the effect of the addition is the same. Examples 15 to 17, Comparative Examples 10 and 11 The same procedures as in Example 1 were carried out except that the blending temperature of the various raw materials for the vinyl chloride resin composition of the present invention was changed. The blending temperatures and results are shown in Table 5.
However, calcium carbonate (0.1 PHR) and silicone oil (0.1 PHR) were added during cooling.

[Table] As is clear from the above results, the higher the blending temperature, the faster the plasticizer absorption rate, and the faster the plasticizer is absorbed. To explain this in relation to the experimental results above, at 70°C, the amount of plasticizer remaining on the surface of the PVC resin particles is too large even after long-time mixing, so even with the addition of charcoal (0.1 PHR), The powder flowability of the resulting compound is poor. On the other hand, at a blending temperature of 140°C, the plasticizer is absorbed in a short time, leaving too little plasticizer remaining on the particle surface. However, since silicone oil is added together with calcium carbonate, the silicone oil absorbs calcium carbonate into the PVC resin particles. Functions to adhere to surfaces. Therefore, the powder fluidity is also good in this case. However, when blending at 140°C, some of the PVC resin particles in the blend melt and gel, and the gelled particles aggregate together, resulting in a large number of large particles. It causes Therefore, in order to use such a vinyl chloride resin composition in processing by the fluidized dipping method, it is necessary to remove the large particles in advance, and the large particles become a substantial loss. Furthermore, at 70°C, the blending condition as well as the powder fluidity is poor, and at 140°C, the blending workability is poor. Therefore, the blending temperature is 80~
130℃ is desirable.

Claims (1)

[Claims] 1. 100 parts by weight of vinyl chloride resin powder, 25 to 25 parts by weight of plasticizer
A vinyl chloride resin composition for fluidized dipping, which contains 100 parts by weight, 0.01 to 0.5 parts by weight of fine powder of an inorganic or organic substance having a particle size of 10 to 100 mμ, and 0.01 to 0.3 parts by weight of silicone oil. 2. Heat the vinyl chloride resin powder and plasticizer at 80°C to 130°C.
After mixing at ℃ and the plasticizer is completely absorbed into the vinyl chloride resin powder, a fine powder of an inorganic or organic substance with a particle size of 10 to 100 mμ is mixed, and silicone oil is mixed with the vinyl chloride resin powder and the plasticizer. A method for producing a vinyl chloride resin composition for fluidized dipping, which comprises mixing before, during or after mixing.