KR100767063B1 - Biodegradable synthetic resin composition and preparing method for the same - Google Patents

Abstract

The present invention relates to a latent heat-functional biodegradable synthetic resin composition and a method of manufacturing the same. More specifically, the phase-transfer material having a latent heat function is used as a core, and the composition of the wall material is improved to encapsulate the biodegradable synthetic resin and By mixing, the existing biodegradable synthetic resins have low thermal properties, improve the problems of poor mechanical properties, and can control the temperature due to the introduction of a latent heat function, thereby further enhancing the thermal stability of the biodegradable synthetic resins. The present invention relates to a latent heat functional biodegradable synthetic resin composition and a method for producing the same, which can be applied and have sufficient biodegradability.

Biodegradable resins, latent heat, encapsulation

Description

Biodegradable synthetic resin composition and preparing method for the same

Figure 1 is an electron micrograph of the latent heat powder of the present invention prepared by Example 1.

Figure 2 is a graph showing the results of measuring the latent heat functionality by Experimental Example 3 using the latent heat functional biodegradable synthetic resin of the present invention prepared in Example 2 and the biodegradable resin of Comparative Example 1.

3 is a graph showing the results of the calorie test (DSC) according to the temperature change of the phase change material itself (paraffin, heat storage capacity 226.5 J / g) used in the embodiment of the present invention, the heat radiation temperature range is 15 ~ 25 ℃ The latent heat temperature range was found to be 25 to 35 ° C.

Figure 4 is a graph showing the calorie test results according to the temperature change of the latent heat powder (heat storage capacity 53.07 J / g) prepared in Example 1 of the present invention, the heat radiation temperature section is 32 ~ 22 ℃, the latent heat temperature section Was found to be 27 to 37 ° C.

FIG. 5 is a graph showing a calorie test result according to temperature change of a latent heat functional biodegradable resin (heat storage capacity 34.82 J / g) prepared according to Example 2 of the present invention, and a heat radiation temperature range is 18 to 30 ° C. The temperature range was found to be 23 ~ 36 ℃.

Figure 6 is a process chart showing briefly the latent heat powder production method of the present invention.

The present invention relates to a latent heat functional biodegradable synthetic resin composition and a method for manufacturing the same, and more particularly, to a phase change material having a latent heat function as a core material, and to improve the composition of the wall material to encapsulate and mix it with a biodegradable synthetic resin, It is possible to improve the thermal stability of biodegradable synthetic resins by improving the thermal stability of biodegradable synthetic resins by improving the problem that the synthetic resins have low thermal properties and poor mechanical properties and by controlling the temperature due to the introduction of latent heat function. It relates to a latent heat functional biodegradable synthetic resin composition and a method for producing the biodegradable enough to expect a natural friendly effect.

In general, synthetic resins, which are polymer compounds obtained by artificially synthesizing raw materials such as coal, petroleum, and natural gas, which are fossil fuels, have characteristics such as processability, strength, hardness, corrosion resistance, weather resistance, water resistance, and durability, and are free of coloring and beautiful in color. It is widely used in various fields.

 However, despite the above excellent characteristics, its consumption is not decomposed in the natural state, causing serious environmental pollution during waste treatment of various products to which they are applied, and due to the depletion of fossil fuels, its consumption is gradually increased through international regulations mainly in developed countries. It is a trend that is reducing or restricting. First of all, some products are prohibited from import and export, and it is urgent to develop materials that can replace synthetic resins due to the rising price of synthetic resin raw materials due to high oil prices.

As a material to replace the polymer synthetic resin prepared by using fossil fuel having the above problems, there is a biodegradable synthetic resin using various grains which can be easily obtained from the surroundings.

However, the biodegradable synthetic resins are currently in various developments, and are already used in some products, but they are limited to disposable products.

This is because the biodegradable synthetic resin is difficult to synthesize with other materials, and even if the synthesis is made, the conditions required for the process of meeting the desired physical properties are very complicated and sensitive manufacturing methods have problems. The low productivity due to the need for devices and the price increase of the product are pointed out as problems.

As a result, biodegradable resins are used only in products in specific fields. Therefore, the versatility applicable to products of various fields remains a problem to be solved.

In addition, aliphatic polyester resins known as biodegradable resins have a problem in that they soften easily even at relatively low temperatures of 60 to 70 ° C. due to the low crystallinity of the main chain, and easily crystallize when subjected to heat.

On the other hand, phase change material (PCM), which has latent heat characteristics such as storage and release of thermal energy by phase transition, has various latent heat characteristics according to the type of material, and is selectively used according to its temperature characteristics. Techniques related to the use of such latent heat are well known.

As a technique related to the use of the phase change material described above is known.

Korean Laid-Open Patent Publication No. 2004-81115 discloses a use of a composite material of a phase change material and a polymer resin, which is applied to a cooling device for electric and electronic parts.

Korean Patent No. 10-0337025 discloses a method for producing a microcapsule type latent heat particulate slurry encapsulated with melamine-formaldehyde resin for use as a phase transfer material as a heat storage and heat supply medium.

Korean Patent No. 10-0263361 has a deterioration characteristic so that the phase transition material improves heat exchange rate due to high latent heat density and atomization during dissolution and solidification process, and prevents agglomeration of fine particles and maintains heat exchange rate even during repeated phase changes. It is introduced that the microencapsulated with urea, melamine, gelatin, etc., can be used for cooling and heating.

However, the above technologies are simply mixed with the phase change material and the polymer resin, and are simply combined to use the functions of latent heat and heat absorption and release of the phase change material, or it is considered to consider only stability when encapsulating the phase change material (micro).

Accordingly, the inventors of the present invention have tried to solve the above problems.

As a result, the latent heat powder prepared by re-coating the outer surface of the wall material with polyvinyl acetate (PVA) while encapsulating the phase change material as a core material with a sheeth, and the biodegradable synthetic resin and When the resin is prepared by mixing, the low mechanical properties of the biodegradable synthetic resin can be improved, as well as excellent latent heat effect and biodegradation were found.

In particular, when the polylactic acid (PLA) is introduced as a biodegradable synthetic resin, softening and non-crystallization did not proceed even at high temperatures, and it was confirmed that the compatibility with the latent heat powder was excellent.

The present invention satisfies requirements such as productivity improvement and price reduction, thereby increasing economical efficiency and providing latent heat function, thereby being applied to various industrial fields such as devices requiring temperature maintenance and devices concerned about performance degradation due to heat generation. I think you can.

In addition, according to the present invention it can be produced a latent heat functional biodegradable synthetic resin that can satisfy the purpose of environmental pollution prevention at the same time.

Accordingly, an object of the present invention is to provide a latent latent powder and a method of manufacturing the encapsulated phase change material having improved latent thermal properties and mechanical strength.

It is another object of the present invention to provide a latent heat-functional biodegradable synthetic resin composition to which the latent heat powder encapsulated with the phase change material is applied and a method of manufacturing the same.

The present invention is a core material (core), the gelatin, melamine resins, anionic acrylic resins, casein selected from one or two or more mixtures of the casein (sheeth), the outer surface of the wall material is polyvinyl It is characterized by a latent heat powder encapsulated with a transition material coated with acetate (poly vinyl acetate, PVA).

In another aspect, the present invention comprises the steps of: 1) preparing an aqueous solution of a subwall material comprising one or a mixture of two or more selected from gelatin, melamine resin and anionic acrylic resin; 2) mixing and stirring by adding a phase change material for the core material to the aqueous solution of step 1); 3) mixing the aqueous solution of the main wall material containing one or two or more of the mixture selected from gelatin, melamine resin, casein and anionic acrylic resin to the mixture of step 2), and the sub-wall material and the main wall material Adding an equal amount of purified water and an aqueous solution of a phase change material for the core material and the same amount of purified water, followed by stirring for 10 to 30 minutes while maintaining 9,000 to 11,000 rpm; 4) polymerizing the emulsion of step 3) while maintaining 2,000 to 3,000 rpm in the range of 45 to 75 ℃; And 5) adding 1 to 2 parts by weight of polyvinylacetate solids to 100 parts by weight of the total polymer after the completion of the polymerization in step 4), and cooling the temperature to 35 to 40 ° C. while maintaining 2,000 to 3,000 rpm. It characterized in that the method for producing a latent heat powder encapsulated with a phase change material comprising the step of adjusting to the range of 8 to 8.5 to terminate the reaction and then dried and powdered.

In another aspect, the present invention is characterized by a latent heat functional biodegradable synthetic resin composition comprising 90 to 50% by weight of biodegradable synthetic resin, and 10 to 50% by weight of latent heat powder encapsulated phase change material.

In another aspect, the present invention is the step of dehumidifying the composition comprising 90 to 50% by weight of biodegradable synthetic resin and 10 to 50% by weight of latent heat powder encapsulated with phase change material, followed by pelletizing by heat mixing and extruding the pellets, and crystallizing the pellets. It includes a method for producing a latent heat functional biodegradable resin comprising a step.

Hereinafter, the present invention will be described in detail.

The present invention encapsulates a phase-transfer material having a latent heat function by encapsulating the composition of the wall material and mixing it with a biodegradable synthetic resin, thereby improving a problem that existing biodegradable synthetic resins have low thermal properties and poor mechanical properties, and introduce a latent heat function. The thermal stability of the biodegradable synthetic resin can be further strengthened, so that the thermal stability of the biodegradable synthetic resin can be further applied, and can be applied to various industrial fields. It relates to a manufacturing method.

Hereinafter, the latent heat powder in which the phase change material of the present invention is encapsulated will be described in detail for each component.

In the latent heat powder of the present invention, a phase change material is used as a core, a gelatin, melamine resin, anionic acrylic resin, casein, and the like, or a mixture of two or more thereof is selected as a sheet material, and the wall material The outer surface is coated with polyvinylacetate.

The phase change material may be a paraffinic hydrocarbon having a melting point in the range of 15 to 40 ° C. and a heat storage capacity of 200 to 260 J / g, in particular a melting point of 15 to 37 ° C., and a heat storage capacity of 200 to 260 J / g. It is better to use a range.

The wall material is one or two or more subwall materials selected from gelatin, melamine resin and anionic acrylic resin, and one or two or more main wall materials selected from gelatin, melamine resin, casein and anionic acrylic resin. It is preferable that it consists of.

In addition, the latent heat powder of the present invention is characterized in that the polyvinyl acetate (PVA) is coated on the outer surface of the wall material, and the stability by the mechanical external force of the latent heat powder is improved by coating the polyvinyl acetate. When applied to the application it is possible to prevent the risk of breaking the capsule, thereby expanding the scope of application.

The latent heat powder of the present invention generally has a micro size diameter, and generally has a diameter in the range of 1 to 10 μm, which is good in terms of mechanical strength and apparent surface smoothness when applied to plastic resins and the like.

Such a method of manufacturing the latent heat powder of the present invention will be described in detail for each step, and an accompanying drawing of the latent heat powder manufacturing process of the present invention is briefly shown in FIG. 6.

As an step 1), an aqueous solution of a subwall material including one or a mixture of two or more selected from gelatin, melamine resin and anionic acrylic resin is prepared.

The aqueous solution is preferably prepared to contain 18 to 22% by weight of the subwall material in terms of yield of latent heat powder and ease of manufacturing process.

As a step 2), the phase change material for the core material is added to the aqueous solution of step 1), followed by mixing and stirring.

As the phase change material for the core material, paraffinic hydrocarbons are used in the present invention. The phase change material may be a paraffinic hydrocarbon having a melting point in the range of 15 to 40 ° C. and a heat storage capacity of 200 to 260 J / g. It is preferable to use a melting point in the range of 15 to 37 DEG C and a heat storage capacity in the range of 200 to 260 J / g.

3) mixing the aqueous solution of the material for the main wall material comprising one or two or more mixtures selected from gelatin, melamine resin, casein and anionic acrylic resin, etc., to the mixture of step 2) as a step; The total amount of the aqueous solution of the main wall material and the phase change material for the core material and the same amount of purified water are added, followed by stirring to emulsify.

At this time, the use ratio of the material for the sub-wall material, the material for the main wall material and the phase change material for the core material is preferably included in the weight ratio of 19 to 22: 19 to 22: 56 to 58 weight ratio. At this time, if the ratio of the wall material including the sub-wall material and the main wall material is small, the encapsulation does not occur properly. When the injection and extrusion are carried out by mixing with the biodegradable resin, the wall is weak and there is a problem that the phase transition material used as the core material flows out. On the contrary, if the ratio of the wall material is high, the capsule wall becomes thick and the phase change reaction to external heat becomes difficult, and since the content of the core material is relatively low, sufficient latent heat effect is not obtained.

Although the said emulsification is made while stirring at high speed, it is preferable to emulsify by stirring for 10 to 30 minutes, maintaining 9,000-11,000 rpm. At this time, if the stirring speed is less than the above range, the size of the capsule produced by the emulsification is not large to achieve micronization, and there is a problem that the capsule is destroyed during injection and extrusion, and if the stirring speed is too fast, the capsule exceeds the above range. The boundary between the continuous phase (wall material) and the discontinuous phase (core material) of the film may not be encapsulated, and the problem of phase transition material flowing out to the surface of the injected and extruded products may occur. The emulsification is maintained for 10 to 30 minutes while maintaining the stirring speed, if the emulsification time is less than 10 minutes, the capsule is not large enough to wrap the phase transition material with the main wall material and the sub-wall material, if more than 30 minutes The thickness of the wall material is too thin or the size of the capsule is too small, there is a problem that the phase-transfer material does not function as an encapsulated capsule.

As a step 4), the emulsion of step 3) is polymerized while being kept stirred in a predetermined temperature range.

Preferably, the polymerization is performed while maintaining 2,000 to 3,000 rpm in the range of 45 to 75 ° C., and the temperature is slowly increased when heat polymerization using a water bath. Preferably, the temperature is increased at a rate of 7 to 10 ° C./hour. The agitation is maintained at 2,000 to 3,000 rpm, and if the stirring speed is less than the above range, the emulsified capsules stick together and coagulate, and there is a problem of separating the core material and the wall material of the emulsified capsule, The size of the wall material, which is a continuous phase of the capsule, is continuously reduced, so that the phase transition material, which is a core material, is not properly encapsulated. The emulsion polymerization is carried out for a predetermined time while monitoring the reactivity conditions such as temperature, time and stirring, it is good to perform for 4 to 5 hours.

As a step 5), after the polymerization in step 4) is completed, polyvinylacetate is added and cooled with stirring, the pH is adjusted to terminate the reaction, and then dried and powdered.

While observing the progress of the emulsion polymerization in step 4), the polymerization reaction temperature is gradually increased at 45 ° C. and when the emulsion polymerization is completed at the time of 70 ° C., polyvinylacetate is added thereto. The polyvinylacetate solid content is added in an amount of 1 to 2 parts by weight. The above-mentioned polyvinyl acetate solids are added and cooled while maintaining the stirring speed at 2,000 to 3,000 rpm. The cooling is preferably performed gradually, and the cooling is preferably performed while maintaining the speed of 10 to 15 ° C / hour. As the cooling proceeds, when the temperature of the reactants reaches about 40 ° C., the pH is adjusted to about alkaline in the range of 8.0 to 8.5 to terminate the reaction. The above pH adjustment is performed using an alkali agent, and may also be performed using an aqueous ammonia solution. When the reaction is finished, they can be dried and powdered to obtain a latent heat powder in which the phase change material of the present invention is encapsulated.

Hereinafter, the latent heat functional biodegradable synthetic resin composition of the present invention will be described in detail for each component.

The latent heat functional biodegradable synthetic resin composition of the present invention comprises 90 to 50% by weight of biodegradable synthetic resin and 10 to 50% by weight of latent heat powder in which a phase change material is encapsulated.

The biodegradable synthetic resin can be applied to all biodegradable synthetic resins, but preferably aliphatic polyester resin, copolymer of aliphatic polyester resin and aromatic polyester, polylactic acid and polycaprolactone [poly (ε) -caprolactone)] or the like, or a mixture of two or more thereof is preferably used.

When mixing and using the said biodegradable synthetic resin, you may use it, including an aliphatic polyester resin and polylactic acid in 100: 0.01-50 weight ratio.

As the biodegradable synthetic resin, the polyester resin may be an aliphatic polyester resin alone or a copolymer of an aliphatic polyester resin and an aromatic polyester resin.

For example, as the aliphatic polyester resin, -CH ₂ -is 1 between alcohol groups such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. The ester bond is formed between -6 diols introduced and hydroxy acids with 1-6 introduced -CH ₂ -between carboxylic acid groups such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, and the like. It is good to use that. The aromatic polyester resin is a diol having 1 to 6 -CH ₂ -introduced between an alcohol group, a dimethyl terephthalate or terephthalate having a benzene ring introduced between a carboxylic acid group and 1 to 6 -CH _2- . It is possible to use those in which the dicarboxylic acid introduced forms an ester bond.

The amount of the biodegradable synthetic resin is 50 to 90% by weight of the total composition, when the amount of the biodegradable synthetic resin is less than 50% by weight, the amount of latent heat powder is relatively increased so that the mechanical properties suitable for various industrial applications cannot be satisfied. If the amount of the biodegradable synthetic resin exceeds 90% by weight, there is a problem that the efficiency of the latent heat function is lowered, and the amount of the latent heat powder is relatively decreased, so that the latent heat function is not sufficiently expressed.

The latent heat functional biodegradable synthetic resin composition of the present invention is easily softened even at low crystallinity and relatively low temperature of the existing biodegradable synthetic resin, and is decrystallized when subjected to heat to solve the problem of deterioration in strength by using latent heat powder and at the same time, It is characterized by being granted.

That is, the latent heat powder is an encapsulated phase change material, and selects a component constituting the wall material of the capsule, and in particular, by re-coating the outer surface of the wall material with polyvinyl acetate, the strength is strengthened while maintaining the latent heat function, and thus it is not easily broken. The above-described effect can be achieved by adding a non-degradable property to the biodegradable synthetic resin.

In addition, when the latent functional biodegradable synthetic resin composition of the present invention is added to the specifically prepared reinforcing agent can be expected to further improve the strength.

That is, such as the biodegradable resin and the latent heat of powder total amount may be used in addition to the reinforcing agent 5-10 parts by weight per 100 parts by weight, the reinforcing agent is a powder of a mixture of polymer resin and a powder of calcium carbonate (CaCO _3), pellet the It can be prepared and used as a dosage form. The polymer resin can be selected and used according to the properties of the biodegradable synthetic resin, specifically, the polymer resin is polylactic acid (PLA), polycaprolactone (PCL), polyhydroxy butyl acid (poly-hydroxy butyric acid) and D- One kind or a mixture of two or more kinds selected from hydroxy butyric acid (D-3-Hydroxy butyric acid) and the like can be used. In particular, when the size of the calcium carbonate is adjusted to be used in the range of 1 to 10 μm, an effect of improving the flowability of the biodegradable resin may be obtained. If the size of the calcium carbonate is too small, it is less than the above range. To reduce or refine the process is difficult, if the size is too large, there may be a problem of poor compatibility with the polymer resin or weakening the mechanical properties.

When the reinforcing agent is used, not only the mechanical strength of the latent functional biodegradable synthetic resin composition is improved, but also the melt index (MI) is improved, thereby improving flowability. In addition, when the latent heat powder in which the phase change material is encapsulated absorbs or releases heat, a change in volume is caused. When the reinforcing agent is used, it also absorbs into the pores of calcium carbonate included in the reinforcing agent to protect the capsule from breaking. To perform.

The reinforcing agent comprises 80 to 90% by weight of the polymer resin and 10 to 20% by weight of calcium carbonate (CaCO ₃ ) in an average size of 1 to 10 ㎛ range, where the amount of the polymer resin in the mixture is relatively carbonate Since the amount of calcium increases, the compatibility of inorganic calcium carbonate and biodegradable resins decreases, and the flowability is excessively increased, which makes injection and extrusion molding difficult. Due to the strength reinforcement and flowability improvement, the protection capacity of the capsule is not enough, there is a problem that the capsule is broken or the machine is unreasonable due to the pressure increase during injection and extrusion.

Additionally, when the curing agent is added to the latent functional biodegradable synthetic resin composition of the present invention, an improvement in mechanical strength can be expected.

Such a curing agent may be selected from natural latex (lava), polar caprolactone (PCL), and aliphatic polyester, and the like, and as the aliphatic polyester, it is preferable to use a strong rubbery material, and the curing agent may be used as the biodegradable synthetic resin. 0.5 to 2.0 parts by weight may be used based on 100 parts by weight of the latent heat powder. When the curing agent is used, the impact strength generated when the biodegradable synthetic resin and the latent heat powder are mixed and blended is more preferable. When the amount is more than 2.0 parts by weight, the hardness may be reduced during injection molding.

In addition to the above reinforcing agents and curing agents, additives commonly used in the art may be appropriately added according to the choice of those skilled in the art according to the use of the composition.

Such additives may include stabilizers, antioxidants, ultraviolet (UV) stabilizers, slip agents, fillers, dispersants, and coupling agents, and the amount of the additive is 100 parts by weight of the total amount of the biodegradable synthetic resin and latent heat powder. With respect to the total amount used is preferably adjusted to add within 50 parts by weight.

Specifically, the stabilizer may be used trimethyl phosphate, phospheric acid, triperiic acid, triphenyl phosphate and the like, the amount of use is 0.01 to 10 with respect to 100 parts by weight of the total amount of the biodegradable synthetic resin and latent heat powder Parts by weight.

As the antioxidant, commercially available Irganox series, Ultranox series, and the like may be used. The amount of the antioxidant is 0.01 to 10 parts by weight based on 100 parts by weight of the total amount of the biodegradable synthetic resin and the latent heat powder. .

The UV stabilizer may be a UV stabilizer of Hals series (HALS, sterically hindered amine), the amount is 0.01 to 10 parts by weight based on 100 parts by weight of the total amount of the biodegradable synthetic resin and latent heat powder.

The slipping agent (slipping agent) may be used calcium stearate, zinc stearate, polyethylene wax (PE WAX), general wax (WAX) and the like, the amount used is 100 parts by weight of the total amount of the biodegradable synthetic resin and latent heat powder It is 0.01-10 weight part.

As the filler (Talc), calcium carbonate, limestone (Limestone), titanium dioxide (TiO ₂ ), carbon black, and the like can be used, the average particle diameter of these is selected to use 0.01 ~ 10 ㎛ It is preferable that the amount is 0.01 to 50 parts by weight based on 100 parts by weight of the total amount of the biodegradable synthetic resin and latent heat powder.

The dispersant is added for compatibility between the resins used, and carboxylated polyethylene, phthalic acid, stearic acid, and the like may be used, and the amount of the dispersant may be 0.01 to 100 parts by weight based on the total amount of the biodegradable synthetic resin and the latent heat powder. 10 parts by weight.

Hereinafter will be described in detail step by step the production method of the latent heat functional biodegradable synthetic resin of the present invention.

That is, dehumidifying the composition comprising 90 to 50% by weight of the biodegradable synthetic resin and 10 to 50% by weight of the latent heat powder in which the phase change material is encapsulated, followed by pelletizing by heat mixing and extruding the pellet, and crystallizing the pellet. Afterwards, a latent functional biodegradable synthetic resin is prepared.

Since the biodegradable synthetic resin is very vulnerable to moisture, the present invention dehumidifies synthetic raw materials including biodegradable synthetic resin and latent heat powder, respectively, in order to prevent degradation of the physical properties caused by the above-mentioned moisture. The dehumidification is preferably made to be less than 0.1% of the moisture content, the method of dehumidification is not particularly limited, but in general, it is convenient to use a dehumidifying dryer.

The heat mixing is performed for 4 to 7 hours while maintaining a speed of 10 to 30 rpm in the temperature range of 70 ~ 90 ℃. If the heating temperature is low, it is difficult to crystallize, and if high, the encapsulated core material (phase transition material) has a problem of leaking to the outside of the capsule, and if the stirring speed is lower than the above range, the problem that the pellets stick to each other in the initial crystallization step If exceeded, the capsule may be damaged by impact. If the heat mixing time is less than 4 hours, crystallization is difficult, and if it is more than 7 hours, the capsule may be damaged.

The above mixing is usually performed using a mixer used in the art, and preferably, a (super) mixer is used.

The mixture is subjected to pelletizing through a process of thinly extruding through an extruder, cooling, and then cutting finely. The extrusion temperature during extrusion is preferably carried out in a range not exceeding 200 ℃, preferably from 140 to 153 ℃, more preferably from 152 to 153 ℃. At this time, when the extrusion temperature exceeds 200 ℃, the loss of the capsule is large. The extrusion is preferably carried out in a pressure range of 60 ~ 110 kg / ㎠. Pelletization is carried out by the extrusion as described above, after the pelletization is stirred in a range of 70 ~ 90 ℃ (10 ~ 30 rpm) to dehumidify and dry to prevent the pellets from sticking.

Crystallization is carried out after the pelletization, and this crystallization is preferably performed while dehumidifying and drying at 70 to 90 ° C. for 4 to 7 hours.

On the other hand, the latent heat functional biodegradable synthetic resin composition of the present invention can be used in the molding of the case and parts of various IT devices, the latent heat powder encapsulating a phase change material having a melting temperature before the performance degradation due to overheating when using them In case of use, the temperature of the applied device may be adjusted in a desired range, that is, in the range of about 28 to 35 ° C.

The present invention is not limited to devices that can be used, but can be used in cases or internal parts of IT devices such as mobile phones, laptops, computers, and various monitors. In particular, electromagnetic waves generated from these devices are shielded by phase change materials. .

This is because when the encapsulated phase change material is in a liquid state or solid state due to phase change, it is close to the gel, and the electromagnetic wave (EMI) generated from the device passes through the phase change material in the part or case, and its wavelength cancels. As a result, it is judged that a large amount of electromagnetic waves are shielded.

In addition, the latent heat-functional biodegradable synthetic resin composition of the present invention prepared as described above can sufficiently suppress the deformation of the resin caused by excessive rise of heat, so that heat is generated to have a problem of deterioration in physical properties or a temperature in a certain range. It can be applied to a variety of devices, such as want to maintain it is expected to be excellent in its industrial usability.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the following Examples.

Example 1 Preparation of Latent Heat Powder

30 g of paraffin (heat storage capacity 226.5 J / g) is added to 29 g of anionic acrylic resin (70% aqueous solution) aqueous solution as a phase change material for the core material, followed by mixing and stirring, and 29 g of melamine resin (70% aqueous solution) aqueous solution 12 g of purified water was added thereto, followed by emulsification with high speed stirring for 10 to 12 minutes while maintaining 10,000 rpm.

The emulsion was slowly heated and polymerized using a water bath and kept at 2,000 rpm while stirring at room temperature for 4 hours at 70 ° C.

When the polymerization was completed, 2 g of the total polymer polyvinylacetate solid was added and the temperature of the polymer was slowly cooled to 40 ° C. for 2 hours while maintaining 3,000 rpm. Moisture was evaporated to dryness by dehumidification drying to obtain latent heat powder (water content less than 0.1%) encapsulated in the phase change material of the present invention.

The latent heat powder prepared above was observed under an electron microscope to confirm that a micro-sized capsule having an average size of 5 μm was formed, and the results are shown in FIG. 1.

Experimental Example 1 Measurement of Properties of Latent Heat Powder

The physical properties of the latent heat powder prepared in Example 1 were measured by the following method, and the results are shown in Table 1 below.

division Property How to measure Tensile Strength (MPa) 29.8 ASTM D 638: 2003 Elongation (%) 11 Flexural Strength (MPa) 38.6 ASTM D 790: 2003 Impact strength (J / m) 31.4 ASTM D 256: 2003

Example 2: Preparation of latent functional biodegradable resin

15 g of latent heat powder prepared in Example 1 and 35 g of polylactic acid (PLA) as biodegradable resin were dehumidified with a dehumidifying dryer for 1 hour at 70 ° C., respectively, and then maintained at a speed of 10 to 30 rpm at 80 ° C. Heat-mix for 5 hours, extrude thin and long to the temperature range of 140-153 ℃, the pressure range of 60-110 kg / cm <2>, and make it into an average 4mm size, and then dehumidify and dry at 70-90 degreeC for 4-7 hours. And crystallization to prepare the latent functional biodegradable resin of the present invention.

Example 3: Preparation of latent functional biodegradable resin

A latent heat functional biodegradable synthetic resin was prepared in the same manner as in Example 2, but 5 g of calcium carbonate powder having an average size of 6 μm was added in a heat mixing step.

Examples 4 to 5: Preparation of latent heat functional biodegradable synthetic resin

A latent functional biodegradable synthetic resin was prepared in the same manner as in Example 2, except that 5 g of calcium carbonate powder having an average size of 6 μm (Example 4) and 10 g (Example 5) were added in a heat mixing step.

Comparative Examples 1-3: Preparation of Biodegradable Synthetic Resin

15 g of Comparative Example 1 and the latent heat-functional biodegradable synthetic resin prepared in Example 2 each having the same calcium carbonate as used in Example 3, 15 g (Comparative Example 2), 20 g (comparative example 3) was added, and a biodegradable synthetic resin was prepared in the same manner as in Example 2.

Experimental Example 2: Measurement of Properties

The physical properties of the latent functional biodegradable synthetic resin of the present invention prepared in Examples 2 to 3 and the biodegradable resin of Comparative Example 1 were measured by the following method, and the results are shown in Table 2 below.

division Comparative Example 1 Example 2 Example 3 How to measure Tensile strength (kgf / ㎠) 590 540 585.3 ASTM D 638: 2003 Elongation (%) 7.6 11.2 7.5 Flexural Strength (kgf / ㎠) 730 862.4 1070.7 ASTM D 790: 2003 Impact strength (J / m) 51.1 460.2 587.7 ASTM D 256: 2003

As shown in Table 2, the latent heat functional biodegradable synthetic resin prepared in Example 2 of the present invention can be confirmed that the flexural strength and the impact strength is significantly improved. In particular, in the latent heat functional biodegradable synthetic resin of Example 3, it can be seen that the flexural strength and the impact strength are further improved.

Experimental Example 3 latent heat function check

Physical properties were measured by the following methods using Examples 2 to 3 and Polylactic Acid of Comparative Example 1.

50 g of the latent heat functional biodegradable synthetic resin of the present invention prepared according to Comparative Example 1 and Example 2 were prepared in a 100 g beaker, and then heated in a water bath after installing a thermometer. At this time, the water of the bath was filled to reach the area containing the resin of the beaker so that the heat was evenly transferred to the resin, and the resin was prevented with aluminum foil to prevent exposure to air and air.

While slowly increasing the temperature of the water bath from 20 ° C. to 40 ° C., each time the thermometer reached 40 ° C. was confirmed. The results are shown in FIG. 2.

According to FIG. 2, the time for reaching Comparative Example 1 from 20 ° C. to 40 ° C. was about 17 minutes, and for Example 2, it took 21 minutes. In particular, when reaching 27 ° C., the temperature range was maintained for about 4 minutes. It was confirmed that the endothermic effect to the, the latent heat functional biodegradable synthetic resin of the present invention as a result was confirmed that the latent heat function.

Experimental Example 4 Flow Measurement

The flowability (melt index, MFI) of the latent heat functional biodegradable synthetic resin of the present invention prepared by Examples 2 to 3 and the biodegradable synthetic resin prepared by Comparative Examples 2 to 3 were measured, and the results are shown in Table 3 below. .

division Example 2 Example 3 Comparative Example 2 Comparative Example 3 Melt Index (g / 10min) (MFI, 190 ℃, 2160 g) 4 15 20 30

As shown in Table 3, it can be seen that the flowability is improved as the content of the reinforcing agent is increased. This is a result that can facilitate the universal injection product, it is preferable in terms of controlling the mechanical properties.

As described above, according to the present invention, a latent heat powder excellent in compatibility with a biodegradable synthetic resin can be produced.

In addition, by applying the latent heat powder to the biodegradable synthetic resin, mechanical properties are improved, and the advanced latent heat functional biodegradable synthetic resin composition having excellent latent heat characteristics and biodegradability can be manufactured easily and at a lower cost than a conventional method.

The present invention satisfies requirements such as productivity improvement and price reduction, thereby increasing economical efficiency and providing latent heat function, thereby being applied to various industrial fields such as devices requiring temperature maintenance and devices concerned about performance degradation due to heat generation. I think you can.

In particular, the latent heat-functional biodegradable synthetic resin of the present invention has been confirmed to have an effect of shielding electromagnetic waves, and its application is considered to be more versatile.

Claims (12)

90-50% by weight of biodegradable synthetic resin, The phase change material is a core, the mixture of gelatin, melamine resin, anionic acrylic resin, or one or two or more selected from casein is used as a sheet material, and the outer surface of the wall material is coated with polyvinylacetate. A latent heat functional biodegradable synthetic resin composition, characterized in that it comprises 10 to 50% by weight of a latent heat powder encapsulated with a phase change material. The biodegradable synthetic resin according to claim 1, wherein the biodegradable synthetic resin is selected from aliphatic polyester resins, copolymers of aliphatic polyester resins and aromatic polyesters, polylactic acid, and polycaprolactone [poly (ε-caprolactone)] Or a mixture of two or more kinds of latent heat functional biodegradable synthetic resin compositions. The latent heat functional biodegradable synthetic resin composition according to claim 1, wherein 5 to 10 parts by weight of a reinforcing agent is included with respect to 100 parts by weight of the total amount of the biodegradable synthetic resin and the latent heat powder. 4. The latent heat functional biodegradable synthetic resin composition according to claim 3, wherein the reinforcing agent is a mixture of 80 to 90 wt% of the polymer resin and 10 to 20 wt% of calcium carbonate (CaCO ₃ ) having an average particle diameter of 1 to 10 µm. The method of claim 4, wherein the polymer resin is polylactic acid (PLA), polycaprolactone (PCL), polyhydroxy butyric acid (poly-hydroxy butyric acid) and D-hydroxy butyric acid (D-3-Hydroxy butyric acid) Latent heat functional biodegradable synthetic resin composition, characterized in that one or two or more selected from. The latent heat functional biodegradable synthetic resin composition according to claim 1, wherein 0.5 to 2.0 parts by weight of a curing agent is included with respect to 100 parts by weight of the total amount of the biodegradable synthetic resin and the latent heat powder. 7. The latent heat functional biodegradable synthetic resin composition according to claim 6, wherein the curing agent is selected from natural latex, polycaprolactone (PCL) and aliphatic polyester. 90-50% by weight of biodegradable synthetic resin, The phase change material is a core, the mixture of gelatin, melamine resin, anionic acrylic resin, or one or two or more selected from casein is used as a sheet material, and the outer surface of the wall material is coated with polyvinylacetate. Dehumidifying the composition comprising 10 to 50% by weight of a latent heat powder encapsulated with a phase change material, characterized in that the heat transfer and extrusion are pelletized; And Crystallizing the pellets; Method for producing a latent heat functional biodegradable synthetic resin comprising a. The method of claim 8, wherein the heat mixing is performed for 4 to 7 hours while maintaining a speed of 10 to 30 rpm in the temperature range of 70 ~ 90 ℃. The method of claim 8, wherein the extrusion is carried out in a temperature range of 140 ~ 153 ℃, a pressure range of 60 ~ 110 kg / ㎠. 9. The method of claim 8, wherein the crystallization is performed while dehumidifying and drying for 4 to 7 hours at 70 to 90 ° C. The latent heat-functional biodegradable synthetic resin composition according to claim 1, wherein the phase change material is a paraffinic hydrocarbon having a melting point in a range of 15 to 40 ° C. and a heat storage capacity of 200 to 260 J / g.

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