KR101114489B1 - Method of preparing nano calcium carbonate-vinyl chloride composite resin composition - Google Patents

Abstract

A method for producing a nano calcium carbonate-vinyl chloride composite resin composition is provided.

Method for producing a nano calcium carbonate-vinyl chloride composite resin composition according to the present invention comprises the steps of (a) adding and dispersing 1 to 20 parts by weight of nano calcium carbonate with respect to 100 parts by weight of vinyl chloride monomer in the prepolymerization reactor; (b) prepolymerization step of adding the initiator to make the PVC particle nucleus; (c) 10 to 20 parts by weight of the vinyl chloride monomer is added to the prepolymerization reactor on the basis of 100 parts by weight of the vinyl chloride monomer introduced during the prepolymerization after the completion of the prepolymerization reaction, and then the scale is removed. Transferring it to a post-polymerization reactor; And (d) 30 to 70 parts by weight of the vinyl chloride monomer in advance to the post-polymerization reactor, based on 100 parts by weight of the vinyl chloride monomer introduced into the pre-polymerization reactor, PVC particle nucleus and scale transferred from the pre-polymerization reactor After mixing with the included vinyl chloride monomer, and the step of post-polymerization by adding an initiator, by using the vinyl chloride monomer in the pre-polymerization reactor at the same time to remove the scale and use it directly in the subsequent process The production cost can be reduced by increasing the efficiency and reducing the amount of expensive impact modifiers used.

Description

Method of preparing nano calcium carbonate-vinyl chloride composite resin composition

The present invention relates to a method for preparing a nano calcium carbonate-vinyl chloride composite resin composition, and more particularly, to a method for producing a nano calcium carbonate-vinyl chloride composite resin composition which can improve process efficiency and productivity using a bulk polymerization method. It is about.

In general, vinyl chloride resins are classified into soft and hard products according to their use. In general, soft products are usually produced by using more than 10% plasticizer, while rigid PVC resins typically use less than 10% plasticizer, in addition to mixing various additives such as pigments, processing aids, heat stabilizers and inorganic fillers It is used as a raw material for products such as pipes, window frames, and hard sheets through molding processing methods such as extrusion, calendar, injection, and the like.

Such rigid PVC resins can generally be produced by suspension polymerization (Suspension Polymerization), which has the disadvantage that the molded article is easily destroyed due to the low impact resistance of the resin itself.

To supplement these disadvantages, impact modifiers such as methyl methacrylate-butadiene-styrene (MBS) copolymer, acrylic impact modifier or chlorinated polyethylene (CPE) are added and used. There is a problem that the price is expensive.

In addition, as a method for reinforcing the impact resistance of the hard PVC resin, when the particle size of PCC (Precipitated Calcium Carbonate) having a particle size of 0.07 μm (70 nm) is added, that is, nano calcium carbonate is added, there is an effect of impact reinforcement. (JARadosta. “Low Temperature and Ambient Impact Modification of Polymers with Surface Treated Calcium Carbonate” SPE ANTEC, New Orleans, May 7-10, 1979).

According to the document, it is shown that the extrusion sample which has undergone the multi-step process of extruding and kneading after melt kneading and roll mill press after kneading with addition of 10 parts by weight or more of nano calcium carbonate to 100 parts by weight of PVC resin shows excellent impact reinforcing effect.

This impact reinforcing effect is reported to occur because the high specific surface area of the nano calcium carbonate disperses the impact energy into the polymer medium, the Republic of Korea Patent Publication No. 2005-46827 polymerization using a suspension polymerization process By evenly dispersing nano calcium carbonate evenly and finely in the vinyl chloride in the step, a technique for reducing the amount of conventional impact modifiers has been disclosed, but there is a problem in that the productivity of the suspension polymerization is lower than the bulk polymerization.

In addition, the mass polymerization method can be introduced for mass production, but there is a fatal problem that scale may occur inside the reactor due to the use of nano calcium carbonate, which may cause the reactor to be blocked.

The technical problem to be achieved by the present invention is to reduce the amount of expensive impact modifiers using nano calcium carbonate in order to solve the conventional problems as described above, while being produced when the continuous production process in the reactor It provides a method for producing a nano-calcium carbonate-vinyl chloride composite resin composition which is advantageous for mass production through improvement of process efficiency by not using a separate process of removing residues such as scale, and directly using it in a subsequent process. It is.

In order to achieve the above technical problem,

(a) adding and dispersing 1 to 20 parts by weight of nano calcium carbonate based on 100 parts by weight of the vinyl chloride monomer in the prepolymerization reactor; (b) prepolymerization step of adding the initiator to make the PVC particle nucleus; (c) 10 to 20 parts by weight of the vinyl chloride monomer is added to the prepolymerization reactor based on 100 parts by weight of the vinyl chloride monomer introduced at the time of the prepolymerization after the completion of the prepolymerization reaction, and the scale is removed by stirring. Transferring it to a post-polymerization reactor; And (d) 30 to 70 parts by weight of the vinyl chloride monomer in advance to the post-polymerization reactor, based on 100 parts by weight of the vinyl chloride monomer introduced into the pre-polymerization reactor, PVC particle nucleus and scale transferred from the pre-polymerization reactor After mixing with the included vinyl chloride monomer, it provides a method for producing a nano-calcium carbonate-vinyl chloride composite resin composition comprising the step of post-polymerization by adding an initiator.

Hereinafter, the present invention will be described in more detail.

Method for producing a nano-calcium carbonate-vinyl chloride composite resin composition according to the present invention is to remove the residue such as the scale generated in the pre-polymerization step to remove the blockage phenomenon of the polymerization reactor that can generally occur, and to remove the scale It is advantageous to mass production through improvement of process efficiency by using continuously in later process.

On the other hand, the method for producing a nano calcium carbonate-vinyl chloride composite resin composition according to the present invention (a) adding and dispersing 1 to 20 parts by weight of nano calcium carbonate to 100 parts by weight of vinyl chloride monomer in the prepolymerization reactor (S1 Step), (b) prepolymerization step (S2 step) to add the initiator to make the PVC particle nucleus, (c) based on 100 parts by weight of the vinyl chloride monomer added during the prepolymerization reaction after the prepolymerization reaction is complete 10 to 20 parts by weight of the vinyl chloride monomer is re-introduced into the prepolymerization reactor, the scale is removed by stirring, and then transferred to the postpolymerization reactor (S3 step), and (d) the chloride added to the prepolymerization reactor Based on 100 parts by weight of the vinyl monomer, 30 to 70 parts by weight of the vinyl chloride monomer is pre-injected into the post-polymerization reactor, and the vinyl chloride containing the PVC particle nucleus and scale transferred from the pre-polymerization reactor. After mixing with the monomer, it is a step (S4 step) of the post-polymerization by adding an initiator.

First, in the step S1, a step of dispersing by adding nano calcium carbonate and lipophilic dispersant in the vinyl chloride monomer, in general, calcium carbonate is produced in the field of producing cement industry, rubber, plastic, paint, paper, etc. It is widely used.

The calcium carbonate used in such an industrial field has a particle diameter of several tens to several hundred micrometers, and in the present invention, nano calcium carbonate atomized to a size of 40 to 70 nm particle size is used. When using these atomized nano calcium carbonates, the surface area is increased and the proportion of ions placed on the surface is increased. Therefore, the influence of the surface given to the so-called physical properties of the powder, such as adsorption capacity, adhesion, and cohesion, is greatly increased.

On the other hand, prior to the step S1, in order to further disperse the nano calcium carbonate in the vinyl chloride monomer, as a separate process, a pre-mixing process can be added, for this purpose it may be equipped with a facility such as a stirrer with a high mixing capacity Can be.

On the other hand, the initial bulk polymerization process is difficult to control the process of mixing the vinyl chloride monomer and various additives, so it was a problem to ensure the high quality of the final product, nano calcium carbonate-chloride according to the present invention In the method for preparing a vinyl composite resin composition, the reaction furnace is divided into a violent prepolymerization step first to form a macroscopic mixture in a violent reaction. For example, the polymerization is performed at a stirring condition of 150 RPM or more, and then uniformly. For example, a mild calcium carbonate-vinyl chloride composite resin composition of high quality is prepared by dividing into a post-polymerization step of polymerization under a stirring condition of 50 RPM or less.

Looking back to step S1, the surface of the nano calcium carbonate is hydrophilic, so in order to be dispersed in the vinyl chloride monomer it is necessary to modify the surface with a metal salt such as fatty acid, resin acid.

In the present invention, the surface of the nano calcium carbonate is modified with a fatty acid so as to wet the vinyl chloride monomer. In addition, an additional dispersant may be used to achieve more uniform and fine dispersion in the vinyl chloride.

Such a dispersant may be a monomeric dispersant or a polymer dispersant having an acid such as carboxylic acid group and phosphoric acid group, or a salt thereof so as to dissolve in the organic phase and have affinity with the surface of the nano calcium carbonate. The compound may be compatible.

In detail, the monomer dispersant may be a C1-C30 hydrocarbon series, and the polymer dispersant may be poly (ethylene oxide) and poly (propylene oxide) as its main chain. Polyethers such as)), polymethacrylates of poly (methyl methacrylate) or poly (n-hexyl methacrylate) (poly (n-hexyl methacrylate)) , Polyacrylate-based, poly (ε) including poly (n-propyl acrylate) and poly (n-butyl acrylate) -Selected from polyester series including caprolactone) (poly (ε-caprolactone)) and the like.

The structure of the polymer dispersant may be a homopolymer, a block copolymer or a graft copolymer, and the molecular weight is not particularly limited.

Adsorbers capable of effectively dispersing in the organic phase by interacting electrically and three-dimensionally with the surface of the nano-calcium carbonate can use carboxylic acid, phosphoric acid, and can also be used in the form of a salt in addition to using these, for example, Salts of phosphoric acid or carboxylic acids may be selected from sodium, ammonium, primary to quaternary alkyl ammonium salts.

In addition, any acid that can interact with the surface of the cationic coordinated nano calcium carbonate can be used as the dispersant without particular limitation.

On the other hand, the amount of the dispersant is preferably used 0.05 to 5 parts by weight of lipophilic dispersant based on 100 parts by weight of vinyl chloride monomer. Here, when less than 0.05 parts by weight is used, nano calcium carbonate is precipitated on the vinyl chloride monomer, and when it exceeds 5 parts by weight, bubbles are generated in the vinyl chloride resin which has been passed through the last step, and remain on the surface to heat Lowering of stability, discoloration, etc. may occur.

In the case of using a dispersant to disperse the nano calcium carbonate in the vinyl chloride monomer, the process temperature is suitable 30 to 80 ℃, less than 30 ℃ may cause the dispersing agent to become cloudy or separated, 80 ℃ Is exceeded, it may be pyrolyzed to discolor the PVC resin after the last process.

On the other hand, the dispersion time of the dispersant is preferably 30 to 120 minutes, if the dispersion time is kept less than 30 minutes, the nano calcium carbonate is not uniformly dispersed, the nano calcium carbonate is not uniformly distributed in the resin after the post-polymerization process. In addition to being able to generate scale and exceeding 120 minutes, productivity is lowered throughout the production process.

Next, in the step S2, in the prepolymerization reactor, a polymerization initiator is introduced into a mixed system of the vinyl chloride monomer in which the nanocalcium carbonate is dispersed to generate a PVC particle nucleus. After dispersing the nano calcium carbonate, a polymerization initiator is added to the prepolymerization reaction at a predetermined temperature to form a PVC particle nucleus of 50 to 150 ㎛. Here, when the PVC particle nucleus is less than 50 µm, the particle size of the final product after the post-polymerization process is too small in process control, and a large amount of dust is generated during transfer to the second vendor, which adversely affects workability and worker's health. If exceeding 150 μm, oversize with low quality may occur.

The polymerization initiator is not particularly limited as long as it is commonly used in the art, and for example, an organic peroxide including a peroxide and a peroxydicarbonate compound may be used.

In addition, the polymerization initiator may be used 0.05 to 5 parts by weight based on 100 parts by weight of the vinyl chloride monomer introduced into the prepolymerization reactor.

On the other hand, the polymerization temperature at this time may be from 60 to 75 ℃, if less than 60 ℃, the polymerization conversion is lowered to produce fine PVC powder in a subsequent process, if it exceeds 75 ℃, polymerization conversion rate This may be so high that a large amount of scale may be generated inside the prepolymerization reactor, and thereafter, lumps and oversize may occur during the process.

In addition, polymerization time can be 5 to 25 minutes. If less than 5 minutes, the polymerization conversion rate is lowered to produce fine PVC dust in the subsequent process, and the particle size distribution of the PVC resin can be widened, and if more than 25 minutes, the polymerization conversion rate is increased to the inside of the prepolymerization reactor Large amounts of scale can be generated and oversize and lumps can be generated in subsequent processes.

Next, looking at step S3, by adding a predetermined amount of vinyl chloride monomer to the mixture containing the PVC particle nucleus to remove the scale inside the prepolymerization reactor, and then transfer it to the postpolymerization reactor.

In the general block polymerization process, the blockage of the reactor may occur due to scale residues.

The present invention adds the removal of these scales in a continuous process to prevent occlusion in advance and further utilizes the removed scale directly in subsequent processes. This improves process efficiency and at the same time enables mass production.

To this end, after the step S2 is completed, a certain amount of vinyl chloride monomer is re-introduced into the prepolymerization reactor and stirred to remove the scale, and the removed scale and the mixture including the PVC particle nuclei are transferred to the postpolymerization reactor. . Herein, the vinyl chloride monomer to be added may be 10 to 20 parts by weight, preferably 10 to 15 parts by weight, based on 100 parts by weight of the vinyl chloride monomer introduced during the prepolymerization. When the stirrer is not locked and the stirring efficiency is lowered, the scale is not properly washed, and if it exceeds 20 parts by weight, additional time is required to fill the prepolymerization reactor, so there is a concern that the process efficiency may decrease. In addition, the transferring step is not a chemical reaction, so it is not necessary to provide a separate heating means in order to reduce energy loss such as heating.

Finally, in the step S4, the nano-calcium carbonate having a particle size of 110 to 200 μm is mixed by mixing the vinyl chloride monomer including the PVC particle nucleus and the scale passed through the S3 step and the vinyl chloride monomer newly added to the post-polymerization reactor. It is a step of preparing a vinyl chloride composite resin composition, preferably a particle size of 130 to 170 ㎛. If the particle diameter is less than 110 μm, the particles may be so light that dust may be generated and adversely affect the environment and health of workers in the process of packaging and transporting them. If the particle size is larger than 200 μm, the physical properties of the particles may vary, resulting in processability. Can be lowered.

The vinyl chloride monomer introduced into the postpolymerization reactor may be used in an amount of 30 to 70 parts by weight, preferably 30 to 60 parts by weight, based on 100 parts by weight of the vinyl chloride monomer introduced into the prepolymerization reactor. Here, if less than 30 parts by weight may be used, low quality scales and lumps may be generated, and if it exceeds 70 parts by weight, it may adversely affect the safety of the post-polymerization reactor.

In addition, the polymerization initiator used to prepare the nano calcium carbonate-vinyl chloride composite resin composition in the post-polymerization reactor may be used 0.05 to 5 parts by weight based on 100 parts by weight of the vinyl chloride monomer introduced in the pre-polymerization reactor.

Meanwhile, the polymerization initiator is not particularly limited as long as it is commonly used in the art, and for example, an organic peroxide including a peroxide and a peroxydicarbonate compound may be used.

In addition, the polymerization temperature of the post-polymerization reactor may be 45 to 60 ℃, when the polymerization temperature is less than 45 ℃ high degree of polymerization is lowered meltability, while the polymerization temperature is lowered if the polymerization temperature exceeds 60 ℃ Impact strength of PVC resin can be lowered.

In addition, the polymerization time of the post-polymerization reactor may be selected and applied in 2 to 4 hours in consideration of the polymerization conversion rate. In addition, unlike the prepolymerization reaction having a vigorous stirring condition, in the postpolymerization reaction, the reactant is agitated at 20 to 30 rpm.

On the other hand, the pH control agent, antioxidant, crosslinking agent, etc. which are commonly used to ensure the quality of the whiteness, weather resistance and the like of the nano calcium carbonate-vinyl chloride composite resin composition according to the present invention can be used. In addition, a composite stabilizer, an impact modifier may be used to secure the above-mentioned quality. In more detail, the composite stabilizer including a thermal stabilizer and a lubricant based on 100 parts by weight of the nanocalcium carbonate-vinyl chloride composite resin composition 4 To 6 parts by weight, methyl methacrylate-butadiene-styrene (MBS) copolymer and 2 to 6 parts by weight of polyethylene chloride (CPE) were added and kneaded at 105 DEG C for 20 minutes using a blender, followed by using a HAAKE extruder. A vinyl chloride-based nanocomposite resin composition is prepared.

Hereinafter, the present invention will be described in more detail with reference to preferred examples, but the present invention is not limited thereto.

Example 1

10 parts by weight of nano calcium carbonate and 0.5 parts by weight of a lipophilic dispersant (Lauryl Phosphate, Miwon Co., Ltd.) based on 100 parts by weight of vinyl chloride monomer introduced into a 200-l prepolymerization reactor equipped with a turbine-type impeller. After addition of parts, it was switched to vacuum. And after adding a vinyl chloride monomer, it heated up to 50 degreeC and stirred at 337 RPM for 30 minutes at this temperature, and the nano calcium carbonate dispersion liquid was prepared in the stable vinyl chloride monomer. After dispersing the nano calcium carbonate in the vinyl chloride monomer in the prepolymerization reactor, 0.05 parts by weight of the polymerization initiator di-2-ethylhexyl peroxydicarbonate (OPP) is added to 100 parts by weight of the vinyl chloride monomer introduced into the prepolymerization reactor. After that, the temperature was raised to 70 ° C., and polymerization was performed for 16 minutes to prepare a PVC particle nucleus having a thickness of 120 μm. This was connected to the post-polymerization reactor, the opening and closing device was transferred to the post-polymerization reactor. Next, closing the switch again and operating the impeller at 230 RPM, based on 100 parts by weight of the vinyl chloride monomer introduced into the prepolymerization reactor, 12 parts by weight of vinyl chloride monomer is added to the prepolymerization reactor, and after the filling The apparatus was opened and transferred to the post polymerization reactor. Then, the vinyl chloride monomer containing the PVC particle nucleus and scale transferred from the prepolymerization reactor and the vinyl chloride monomer newly added to the postpolymerization reactor were mixed, and the 500 l postpolymerization reaction with the screw / scraper-type impeller was attached. 60 parts by weight of vinyl chloride monomer was pre-filled in the post-polymerization reactor based on 100 parts by weight of the vinyl chloride monomer introduced from the pre-polymerization reactor to the furnace, and the residual vinyl chloride monomer containing the PVC particle nucleus and scale obtained in the pre-polymerization step was transferred. After the addition of 0.1 parts by weight of 1,1,3,3-tetramethyl butyl peroxy neoecanoate (OND) as a polymerization initiator, the temperature was raised to 54 ℃ and polymerized for 3 hours to finally have a particle diameter containing nano calcium carbonate A nano calcium carbonate-vinyl chloride composite resin composition having a thickness of 150 μm was prepared. Finally, 6 parts by weight of a composite stabilizer containing a heat stabilizer and a lubricant, 6 parts by weight of heavy calcium carbonate (GCC), and methyl methacryl as an impact modifier based on 100 parts by weight of the nanocalcium carbonate-vinyl chloride composite resin composition obtained by the above method. 1 part by weight of late butadiene-styrene (MBS) and chlorinated polyethylene (CPE) were added and kneaded using a blender at 105 ° C. for 20 minutes, and a plate-shaped extruded specimen having a thickness of 3 mm was prepared using a HAAKE twin extruder. Prepared. The processing temperature was increased in the range of about 160 ~ 200 ℃ in the hopper (die) direction and the screw rotational speed was processed at 20 ~ 30rpm to naturally cool the ejected extrudates within 3 minutes.

Example 2

Except that 3 parts by weight of methyl methacrylate-butadiene-styrene (MBS) and chlorinated polyethylene (CPE) were added to the nanocalcium carbonate-vinyl chloride composite resin prepared in the same manner as in Example 1 as an impact modifier. Extruded specimens were prepared in the same manner as in Example 1, and their impact strengths are shown in Table 1 below.

Comparative Example 1

In preparing the general vinyl chloride resin, a vinyl chloride monomer was added to a 200 L prepolymerization reactor in a vacuum state except for the dispersion step of the nano calcium carbonate in the step S1. Thereafter, vinyl chloride resin was prepared through prepolymerization and postpolymerization in the same manner as in Example 1, and methyl methacrylate-butadiene-styrene (MBS) was used as the impact modifier in the vinyl chloride resin as in Example 2. Table 1 shows the impact strength of the extruded specimens prepared in the same manner as in Example 1, except that 3 parts by weight of chlorinated polyethylene (CPE) were added.

Test Example 1

For the extruded specimens obtained through Examples 1 and 2 and Comparative Example 1, a specimen for measuring impact strength was prepared according to ASTM D256, KS B 5522, and KS M 3055, and the impact strength was measured by a prescribed test method. 1 is shown.

division Example 1 Example 2 Comparative Example 1 Charpy Impact Strength (kgCm / Cm) 31.2 39.4 31.7

As shown in Table 1, when looking through Example 2 and Comparative Example 1, the nano calcium carbonate-vinyl chloride composite resin composition according to the manufacturing method according to the present invention shows an excellent impact strength compared to the general vinyl chloride resin. Furthermore, as can be seen through Example 1 and Comparative Example 1, it can be seen that the expensive impact modifiers show similar impact strength despite using about 1/3 part by weight compared to Comparative Example 1. When referring to the results, it can be confirmed that the impact strength is excellent when the impact modifiers are used at the same ratio.

On the other hand, when produced by the suspension polymerization method in the same capacity of the reactor, it is possible to produce three times per day, the production method according to the present invention is possible to produce 15 times per day. Therefore, it can be seen that the productivity of about five times the difference.

In addition, in the manufacturing method according to the present invention, when the removal of the scale is performed as a continuous process, the production can be stopped for removing the existing scale, and further, the loss and the enormous loss of unnecessary external force can be prevented. .

As described above, the method for producing the nano-calcium carbonate-vinyl chloride composite resin composition according to the present invention uses a vinyl chloride monomer in a prepolymerization reactor to simultaneously remove the scale and use it directly in a subsequent step to use raw materials. In addition, it is possible to reduce the amount of expensive impact modifiers used to reduce manufacturing costs and improve productivity.

Claims (8)

(a) adding and dispersing 1 to 20 parts by weight of nano calcium carbonate based on 100 parts by weight of the vinyl chloride monomer in the prepolymerization reactor; (b) prepolymerization step of adding initiator to make PVC particle nuclei; (c) 10 to 20 parts by weight of the vinyl chloride monomer is added to the prepolymerization reactor based on 100 parts by weight of the vinyl chloride monomer added at the time of the prepolymerization after the completion of the prepolymerization reaction to remove scale. Transferring it to a post-polymerization reactor; And (d) 30 to 70 parts by weight of the vinyl chloride monomer is added to the post-polymerization reactor in advance based on 100 parts by weight of the vinyl chloride monomer introduced into the prepolymerization reactor, and the PVC particle nucleus and scale transferred from the pre-polymerization reactor are After mixing with the included vinyl chloride monomer, a method of producing a nano calcium carbonate-vinyl chloride composite resin composition comprising the step of post-polymerization by adding an initiator. The method of claim 1, The particle size of the nano calcium carbonate is a method for producing a nano calcium carbonate-vinyl chloride composite resin composition, characterized in that 40 to 70 nm. The method of claim 1, The surface of the nano calcium carbonate is a method of producing a nano calcium carbonate-vinyl chloride composite resin composition, characterized in that the coating with a fatty acid metal salt. The method of claim 1, The dispersing step further comprises 0.05 to 5 parts by weight of a lipophilic dispersant based on 100 parts by weight of the vinyl chloride monomer. The method of claim 4, wherein The lipophilic dispersant is a calcium carbonate-vinyl chloride composite resin, characterized in that the adsorber having a main chain consisting of C1-C30 hydrocarbon-based, polyolefin-based, polyether-based, polymethacrylate-based, polyacrylate-based or polyester-based Method of Preparation of the Composition. The method of claim 5, The adsorbent is selected from a compound containing phosphoric acid or carboxylic acid. The method of manufacturing a nano calcium carbonate-vinyl chloride composite resin composition. The method of claim 1, The temperature in the dispersing step is 30 to 80 ℃, the holding time is 30 to 120 minutes, the manufacturing method of the nano calcium carbonate-vinyl chloride composite resin composition. The method of claim 1, The temperature in the step of transferring is a method of producing a nano calcium carbonate-vinyl chloride composite resin composition, characterized in that less than 70 ℃.