JP2011052042A - Raw material composition for polyvinyl chloride product, and polyvinyl chloride molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a raw material composition for polyvinyl chloride products capable of producing a comparatively thick polyvinyl chloride product of large mass effect uniformly and easily with no use of energy at all such as electrical energy, gas and heavy oil because no heat treatment is required, and to provide a polyvinyl chloride molded product. <P>SOLUTION: This raw material composition for polyvinyl chloride products can be solidified without heat treatment by adding polyol and an isocyanate compound as a chemical reaction controlling agent for urethanization reaction to a polyvinyl chloride paste sol which is prepared by adding an additive and a diluent to a polyvinyl chloride paste resin. The raw material composition for polyvinyl chloride products is cast into a molding tool, and the polyvinyl chloride molded product is solidified uniformly only by chemical reaction without heat treatment. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides a relatively thick-walled vinyl chloride product having a large mass effect, which can be produced homogeneously and easily without the need for heat treatment and without using any energy such as electricity, gas or heavy oil. The present invention relates to a raw material composition and a vinyl chloride molded product.

Conventionally, vinyl chloride molded products have been widely used in fields such as automobiles, home appliances, building materials, hoses, etc. because of their excellent weather resistance, oil resistance, anti-fogging properties, scratch resistance, moldability, etc. Various material compositions for vinyl chloride products have been proposed (see, for example, Patent Document 1 and Patent Document 2).
These products are made into a product or semi-finished product by forming a paste or sol that is fluid at room temperature by a molding method such as coating, dipping (casting), casting, or rotational molding, and then applying heat to gelation, It is made the final molded product through a melting and cooling process.

FIG. 4 shows a schematic flow diagram of a conventional molding process.
In the figure, “paste resin” means a special vinyl chloride resin having a diameter of 0.02 to 2 μm, and “paste sol” means that this paste resin is added with a liquid plasticizer, diluent, stabilizer, etc. It is fluid at room temperature obtained by mixing and kneading together with the agent. This vinyl chloride paste sol is shaped in the mold at around room temperature, and various vinyl chloride molded products are manufactured through heating, gelation, melting and cooling processes.
As described above, the vinyl chloride molded article is usually processed by a thermosetting resin while vinyl chloride is a thermoplastic resin.

  The heat energy used in this molding process is electricity, gas, kerosene or the like as a heat source. The heating is an external heating method in which the product is heated from the outside, and heat is sequentially transmitted from the surface of the article to be heated to the inside to reach a desired temperature. At this time, a thick product with a large mass effect takes a longer time to increase the desired temperature at the center (time lag) than a thin product with a small mass effect, resulting in a temperature difference between the surface and the center. However, even if the solidification of the surface is completed, the central part exhibits a sol or gel shape, and a phenomenon occurs that neither the inside nor the outside is solidified. On the other hand, when the heating time is lengthened to solidify the central portion, the surface is overheated, and in some cases, a fatal defect state of resin decomposition may be caused.

Therefore, in the external heating method, it is impossible in principle to solidify the inside and outside of the product almost at the same time, and this has been a factor in hindering the development of thick-walled products with a large mass effect.
However, because of its excellent weather resistance, scratch resistance, molding processability, etc., application to thick side grooves and U-shaped grooves, for example, has been studied, and development of thick-walled vinyl chloride products that has been impossible in the past has been developed. It has come to be desired.

JP-A-9-302593 JP-A-9-241460

  The present invention solves the above-mentioned problems and produces a vinyl chloride molded product without using any heat energy, and even a thick product with a large mass effect can be evenly distributed from the surface to the center. The technical problem is that it can be solidified and can be easily manufactured without requiring large-scale equipment.

This time, the present inventor paid attention to the solidification technology of the vinyl chloride paste sol by chemical reaction, and used as the chemical reaction control agent (1) polyester resin and curing agent, (2) epoxy resin and curing agent, and (3) polyurethane resin. As a result of mixing and testing with a vinyl chloride paste sol, the polyurethane resin and the curing agent (3), that is, a compound of polyol and isocyanate, reacted with the vinyl chloride paste sol due to the composition of the raw material composition. The present invention has been completed by finding out that the above-mentioned objects can be achieved by investigating that it has excellent overall properties, such as compatibility, compatibility of materials, freedom of compounding, and application of existing materials. It was.
Therefore, the object of the present invention is based on the facts found by the above-mentioned inventors, and does not require a heat treatment process, only by chemical reaction, and by reducing the influence of mass effect as much as possible. It is to provide a novel raw material composition for a vinyl chloride product and a vinyl chloride molded article that can be shaped from solid to solid.

The raw material composition for vinyl chloride products of the present invention made to solve the above problems is a chemical reaction for urethanizing a vinyl chloride paste sol obtained by adding an additive or diluent to a vinyl chloride paste resin. It is characterized in that a polyol and an isocyanate compound are added as control agents so that they can be solidified without heat treatment.
That is, based on a PVC paste sol raw material, a polyol, which is one component of a reactant, is mixed and dispersed uniformly in a PVC paste sol, and then a two-component isocyanate compound is mixed as a chemical reaction control agent to make urethane. It has an essential feature in that it is a raw material composition that generates a chemical reaction.

  Further, it is preferable to add 10 to 50 parts by weight of the polyol and the isocyanate compound in a total amount with respect to 100 parts by weight of the vinyl chloride paste sol, and this is the invention according to claim 2.

  Furthermore, the vinyl chloride molded article according to claim 3, wherein the raw material composition for vinyl chloride products is put into a mold and solidified only by a chemical reaction without heat treatment. And

  In the invention according to claim 1, since a polyol and an isocyanate compound are added as a chemical reaction control agent for urethanization reaction to a vinyl chloride paste sol obtained by adding an additive or a diluent to a vinyl chloride paste resin, urethane By the chemical reaction (or polyaddition reaction), a shaped molded article can be obtained without using thermal energy. In addition, in this molded product, a chemical reaction that is a urethanization reaction occurs simultaneously in all parts with respect to the vinyl chloride paste sol, so that it is possible to produce a molded product that has a uniform and thick wall and has a large mass effect. .

  Further, as in the invention according to claim 2, if the total amount of polyol and isocyanate compound is 10 to 50 parts by weight with respect to 100 parts by weight of the vinyl chloride paste sol, the vinyl chloride paste sol can be surely uniformly solidified. .

  In the invention according to claim 3, since the raw material composition for vinyl chloride products is put into a mold and solidified uniformly only by a chemical reaction without heat treatment, no thermal energy is required, and Thus, a molded product having a large mass effect can be easily manufactured.

It is a graph which shows the relationship between the mixing amount of an isocyanate compound, and hardness. It is a graph which shows the relationship between the longitudinal cross-section of a molded article, and hardness. It is a schematic flowchart which shows the shaping | molding process of the vinyl chloride molded product of this invention. It is a schematic flowchart which shows the shaping | molding process of the vinyl chloride molded article of a prior art example.

Below, the raw material composition for vinyl chloride products of this invention and the vinyl chloride molded product shape | molded using this are demonstrated.
In the raw material composition for vinyl chloride products of the present invention, a polyol and an isocyanate compound are added as a chemical reaction control agent for urethanization reaction to a vinyl chloride paste sol obtained by adding an additive or diluent to a vinyl chloride paste resin. However, it is characterized in that it can be solidified without heat treatment.
Here, “paste resin” refers to a special vinyl chloride resin having a diameter of 0.02 to 2 μm, and “vinyl chloride paste sol” refers to this vinyl chloride paste resin as a liquid plasticizer, diluent, stabilizer. It has fluidity at room temperature and is obtained by mixing and kneading together with such additives.

  In the present invention, a urethanization reaction (or polyaddition reaction) is carried out by mixing a polyvinyl reactant as a chemical reaction control agent with a one-component polyol reactant and two-component isocyanate compound as a chemical reaction control agent for a vinyl chloride paste sol. Thus, it was found that the sol form (liquid state) can be solidified without heating, and has been completed.

As the vinyl chloride paste resin, commercially available products can be used. This is a particle size of 0.1 to 10 μm produced by emulsion polymerization of vinyl chloride monomer, and the particle shape is close to a true sphere. In order to make this paste resin into a sol, one or more of plasticizers, stabilizers, fillers, diluents, thinning agents, colorants, flame retardants and the like are usually used as compounding agents. . In addition to determining the appropriate addition amount for the paste resin according to the application, the paste resin and the additive are uniformly dispersed in a mixer having a stirring function, and the mixture is stirred and mixed for a predetermined time and fluidity. A PVC paste sol having
Thereafter, in order to remove the air remaining between the solid particles and the air entrained during mixing, defoaming is performed under reduced pressure to obtain a desired PVC paste sol.

A polyurethane raw material is used as a chemical reaction control agent for urethanization reaction (or polyaddition reaction). For this, commercially available polyols and isocyanate compounds can be used.
As is well known, these are many types and are not limited to only one type. For the polyvinyl chloride paste sol, the first liquid polyol (initiator) and the second liquid isocyanate compound (reaction product) The mixed use (polymerization) of can generate a urethanization reaction (or polyaddition reaction).

As for the addition amount of the chemical reaction control agent, it is preferable to add 10 to 50 parts by weight of the total amount of polyol and isocyanate compound with respect to 100 parts by weight of the vinyl chloride paste sol. If the added amount is less than 10 parts by weight, solidification is difficult, while if it is more than 50 parts by weight, sufficient weather resistance, scratch resistance, and moldability are difficult to obtain.
The mixing ratio of the polyol and the isocyanate is preferably a ratio of 5: 2 to 2: 5, and can be adjusted to any hardness by adjusting according to the usage.

The raw material composition for a vinyl chloride product thus obtained can be put into a mold and uniformly solidified only by a chemical reaction without heat treatment to obtain a vinyl chloride molded product.
FIG. 3 shows a schematic flow diagram of the molding process of the present invention. As a molding method, it can be shaped by a general molding method such as coating, dipping (casting), casting, or rotational molding. In the present invention, since it is solidified by urethanization reaction (or polyaddition reaction), conventional heat treatment is unnecessary.

Hereinafter, examples will be described.
100 parts by weight of a polyvinyl chloride paste resin having an average polymerization degree of 850 was put into an eccentric biaxial mixer, stirred at a rotational speed of 1700 rpm / min, various additives were added according to the blending conditions shown in [Table 1], and 40 The mixture was stirred for 50 minutes while adjusting the temperature at a temperature not higher than ° C. to obtain a vinyl chloride paste sol.

  Next, a predetermined amount of polyol (containing no foaming agent) is added to a propeller stirrer with respect to 100 parts by weight of the vinyl chloride paste sol, and mixed and stirred for 3 minutes while paying attention to air entrainment at a low speed of 500 to 700 rpm / min. It was confirmed that uniform dispersion without generation or undispersed state was obtained. Then, the isocyanate compound used as a chemical reaction control agent was added in a predetermined amount and mixed at 1200 rpm / min for 20 to 60 seconds.

After mixing, it was confirmed that the reaction had started, and the mixture was put into a container to obtain a shaped product.
Here, the chemical reaction start time cannot be clearly understood, but the chemical reaction phenomenon occurs in the process where the reaction starts and progresses, and the temperature change (temperature increase) due to heat generation and the liquid viscosity change (viscosity increase) are reaction phenomena. Based on the idea that it will surely appear, we grasped the behavior of these two points and used it as a criterion for container injection.

  Next, in solidifying the vinyl chloride paste sol, the total amount of polyol and isocyanate compound can be solidified if it is 10 weights or more with respect to 100 weight of the vinyl chloride paste sol, but solidification occurs below that. I don't get it. In short, this is nothing but the amount of reaction that occurs with respect to the volume to be reacted. On the other hand, when the amount is more than 50 parts by weight, it is difficult to obtain sufficient weather resistance, scratch resistance and molding processability, which is not preferable.

  As for the quality when solid, in the case of conventional heat-treated products, cracks that are fatal to molded products have not occurred on the surface, but many cracks have occurred in each internal part, In the interlayer boundary observed, there are microcracks that are visible over a ring shape and sites that are widely open. The cause is assumed to be due to the stress caused by the temperature difference between the inside and outside during cooling, and that the surface strength exceeded the internal strength after completion of cooling. As a countermeasure for this, a slow cooling method in which the temperature difference between the inside and outside is reduced so as to minimize the stress is considered, but it is actually difficult in view of productivity.

  On the other hand, the occurrence of cracks is not observed in the molded product due to the chemical reaction of the present invention. This is because the reaction occurs simultaneously in all the internal and external parts from the start to the end of the reaction, so no stress is generated, and even if stress is generated during cooling, the stress itself is small enough not to cause a problem. It is possible.

  In order to demonstrate that the isocyanate compound used as the chemical reaction control agent is not limited to one type, four different types of isocyanate compounds were used. These compounding ratios are shown in [Table 2].

  A test was conducted with respect to changes in the amount and ratio of four types of isocyanate compounds with a fixed polyol, and the resulting molded product as a test material. The surface hardness (●) and internal center hardness (O) were measured using a Shore hardness meter ( D type). The results are as shown in the graph showing the relationship between the amount of isocyanate compound mixed and the hardness shown in FIG. (2-1) to (2-4) in the figure show the isocyanate compounds in [Table 2].

  As shown in FIG. 1, the hardness of all four types of isocyanate compounds increases in proportion to the increase in the amount of mixing. It should be noted that there is little difference between the surface and internal center hardness, and the mixing amount is 24 or 28 parts, there is almost no difference in hardness or minimal difference, and the mass effect is small. Moreover, even if the mixing amount is the same, if the ratio changes in the reverse direction, the altitude tends to decrease, and the hardness difference starts to open slightly. This shows not only high quality in thick-walled products, but also freedom of compounding design depending on the purpose of use, which is a useful material feature.

  Table 3 shows the results of checking for solidification and occurrence of cracks in the vinyl chloride molded product molded by the conventional external heating method and the chemical reaction method of the present invention.

  From the above, compared with the conventional solidification method by external heating and cooling, the chemical reaction method of the present invention can uniformly and advantageously produce a molded product having a large mass effect, that is, a molded product having a large product thickness. It can be confirmed.

Furthermore, the result of having carried out the test which raised thickness and calculated | required the hardness distribution of a longitudinal cross-section is shown in FIG. What can be said from this is that in the reaction, even if the volume is increased, if the mixing amount is appropriate, the obtained molded article does not cause a fatal defect or the like. It can be seen that the mass effect is smaller than the hardness distribution that provides a sound densified quality both inside and outside, and that the reaction takes place over the entire site.
Moreover, in FIG. 2, the location where hardness protrudes in part near surface layer is recognized. It is conceivable that the stirring during mixing is not sufficient, and the concentration of the reactant is locally increased, leading to an increase in hardness. From this event, in order to mix the reactants into the main material, it is important to disperse the reactants uniformly in the main material as well as the basic compatibility and anti-air mixing. It shows.

Claims (3)

  The addition of polyols and isocyanate compounds as chemical reaction control agents for the urethanization reaction to vinyl chloride paste sols obtained by adding additives and diluents to vinyl chloride paste resin, and making it possible to solidify without heat treatment A raw material composition for vinyl chloride products.   The raw material composition for a vinyl chloride product according to claim 1, wherein 10 to 50 parts by weight of the polyol and the isocyanate compound are added in total to 100 parts by weight of the vinyl chloride paste sol. A vinyl chloride molded article, wherein the raw material composition for a vinyl chloride product according to claim 1 or 2 is charged into a mold and uniformly solidified only by a chemical reaction without heat treatment.

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