KR102414310B1 - Coating composition for expandable polystrene bead - Google Patents

Abstract

The coating composition for expandable polystyrene particles of the present invention includes 100 parts by weight of a thermosetting resin comprising 60 to 90% by weight of a phenol resin and 10 to 40% by weight of a melamine resin; 0.5 to 2 parts by weight of a curing agent; 10 to 50 parts by weight of aluminum hydroxide; 10 to 30 parts by weight of expanded graphite; and 6 to 20 parts by weight of the hollow inorganic filler, wherein the weight ratio of the expanded graphite and the hollow inorganic filler is 1:0.2 to 1:2. The coating composition for expandable polystyrene particles may improve flame retardancy, heat insulation, and the like of expandable polystyrene particles and expanded molded articles.

Description

Coating composition for expandable polystyrene particles {COATING COMPOSITION FOR EXPANDABLE POLYSTRENE BEAD}

The present invention relates to a coating composition for expandable polystyrene particles. More specifically, the present invention relates to a coating composition for expandable polystyrene particles capable of improving flame retardancy and heat insulation of an expanded molded article, expandable polystyrene particles coated therewith, and an expanded molded article formed therefrom.

Expandable polystyrene particles are pre-expanded particles of resin particles prepared to foam at a desired density when the foaming agent is diffused and volatilized to the outside air when heated with steam, etc. (Expanded molded article). The molded article manufactured in this way has excellent high strength, lightness, buffering properties, waterproofness, heat retention, and heat insulation, and is used in various fields such as packaging materials for home appliances, boxes for agricultural and fishery products, and insulation materials for construction materials.

Generally, expandable polystyrene particles are prepared by suspension polymerization by adding water, a styrene monomer, a polymerization initiator, and a suitable suspension stabilizer to a reactor, stirring and dispersing, and then raising the temperature to prepare spherical polystyrene particles, and impregnated with a blowing agent. to obtain spherical expandable polystyrene particles, which can be pre-foamed to a desired density and used.

In order to improve the flame retardancy and heat insulation of expandable polystyrene particles (expanded molded article), inorganic materials such as expanded graphite, carbon black, and alumina are applied during particle polymerization, but moldability and fusion properties may be deteriorated, and in case of excessive application, it is rather flame retardant. and thermal insulation properties, etc. may be deteriorated.

Therefore, there is a need to develop expandable polystyrene particles capable of producing an expanded molded article having excellent flame retardancy and heat insulation without deterioration in moldability, etc.

Background art of the present invention is disclosed in Korean Patent Laid-Open No. 2001-0080720 or the like.

It is an object of the present invention to provide a coating composition for expandable polystyrene particles capable of improving flame retardancy, heat insulation, and the like of an expanded molded article.

Another object of the present invention is to provide expandable polystyrene particles coated with the coating composition and an expanded molded article formed therefrom.

The above and other objects of the present invention can all be achieved by the present invention described below.

1. One aspect of the present invention relates to a coating composition for expandable polystyrene particles. The coating composition may include: 100 parts by weight of a thermosetting resin comprising 60 to 90% by weight of a phenol resin and 10 to 40% by weight of a melamine resin; 0.5 to 2 parts by weight of a curing agent; 10 to 50 parts by weight of aluminum hydroxide; 10 to 30 parts by weight of expanded graphite; and 6 to 20 parts by weight of the hollow inorganic filler, wherein the weight ratio of the expanded graphite and the hollow inorganic filler is 1:0.2 to 1:2.

2. In the first embodiment, the coating composition for expandable polystyrene particles may include 40 to 100 parts by weight of a solvent based on 100 parts by weight of the thermosetting resin.

3. In the above 1 or 2 embodiments, the phenolic resin may be a resol-type phenolic resin.

4. In the above 1 to 3 embodiments, the curing agent may include at least one of dodecylbenzenesulfonic acid, sulfuric acid, phosphoric acid, benzenesulfonic acid, ethylbenzenesulfonic acid, paratoluenesulfonic acid, xylenesulfonic acid, and naphtholsulfonic acid.

5. In embodiments 1 to 4, the hollow inorganic filler may be a spherical hollow glass particle.

6. Another aspect of the present invention relates to expandable polystyrene particles. The expandable polystyrene particles are characterized in that the coating composition for expandable polystyrene particles according to any one of 1 to 5 is coated on the particle surface.

7. In the 6th embodiment, the particles may be pre-foamed with a density of 10 to 35 kg/m ³ of the foamable resin composition.

8. In the 7th embodiment, the foamable resin composition may include a styrene-based resin and a foaming agent.

9. Another aspect of the present invention relates to an expanded molded article. The expanded molded article is characterized in that it is formed by filling a mold with the expandable polystyrene particles according to any one of 6 to 8, heating and fusion bonding.

10. In the 9th embodiment, the expanded molded article may have a thermal conductivity of 0.03 to 0.038 W/m·K measured according to ASTM C518.

11. In the 9th embodiment, the foamed molded body may have a total amount of emitted heat measured in accordance with KS F ISO 5660-1 of 2 to 8 MJ/m ² .

The present invention has the effect of providing a coating composition for expandable polystyrene particles capable of improving flame retardancy, heat insulation, etc. of an expanded molded article, expandable polystyrene particles coated therewith, and an expanded molded article formed therefrom.

Hereinafter, the present invention will be described in detail as follows.

The coating composition for expandable polystyrene particles according to the present invention includes (A) a thermosetting resin comprising a phenol resin and a melamine resin; (B) a curing agent; (C) aluminum hydroxide; (D) expanded graphite; and (E) a hollow inorganic filler.

In the present specification, "a to b" representing a numerical range is defined as "≥a and ≤b".

(A) thermosetting resin

The thermosetting resin according to an embodiment of the present invention is coated on the surface of expandable polystyrene particles to improve flame retardancy and moldability of the expanded molded article, and includes a phenol resin and a melamine resin.

In an embodiment, as the phenol resin, a conventional phenol resin may be applied, for example, a resol-type phenol resin may be used. The phenolic resin may have a viscosity measurement value of 1,000 to 2,000 cPs at 25° C., for example 1,200 to 1,700 cPs. In the above range, the expandable polystyrene particles (expanded molded body) may have excellent flame retardancy, heat insulation, moldability, and the like.

In an embodiment, the content of the phenol resin may be 60 to 90% by weight, for example, 70 to 80% by weight based on 100% by weight of the total thermosetting resin. When the content of the phenol resin is less than 60% by weight, there is a risk that the flame retardancy and heat insulation of the expandable polystyrene particles (expanded molded article) may be lowered, and when it exceeds 90% by weight, the moldability of the expandable polystyrene particles (expanded molded article), There is a possibility that strength and the like may decrease.

In an embodiment, as the melamine resin, a conventional melamine resin may be applied, for example, a viscosity measurement value of 25°C may be 500 to 1,500 cPs, for example 800 to 1,200 cPs Expandable polystyrene particles ( The heat insulation, moldability, etc. of the expanded molded article) may be excellent.

In an embodiment, the content of the melamine resin may be 10 to 40% by weight, for example, 20 to 30% by weight of 100% by weight of the total thermosetting resin. If the content of the melamine resin is less than 10% by weight, there is a fear that the moldability, strength, etc. of the expandable polystyrene particles (expanded molded article) may be reduced, and if it exceeds 40 wt%, the flame retardancy of the expandable polystyrene particles (expanded molded article), There exists a possibility that heat insulation etc. may fall.

(B) curing agent

A curing agent according to an embodiment of the present invention may be used without limitation, a conventional curing agent used for curing the thermosetting resin.

In an embodiment, the curing agent may include one or more of dodecylbenzenesulfonic acid, sulfuric acid, phosphoric acid, benzenesulfonic acid, ethylbenzenesulfonic acid, paratoluenesulfonic acid, xylenesulfonic acid, and naphtholsulfonic acid.

In an embodiment, the curing agent may be included in an amount of 0.5 to 2 parts by weight, for example, 0.7 to 1.5 parts by weight, based on 100 parts by weight of the thermosetting resin. When the content of the curing agent is less than 0.5 parts by weight, there is a fear that the curing time increases, and when it exceeds 2 parts by weight, there is a fear that the coating composition of the expandable polystyrene particles may be non-uniform.

(C) aluminum hydroxide

Aluminum hydroxide according to an embodiment of the present invention is coated on the surface of expandable polystyrene particles to reduce the total calorific value of the expanded molded article through endothermic heat, and to improve the flame retardancy of the expanded molded article through dilution of combustible gas. Conventional expandable polystyrene Aluminum hydroxide applied to the particles can be used.

In an embodiment, the aluminum hydroxide may be included in an amount of 10 to 50 parts by weight, for example, 20 to 40 parts by weight, based on 100 parts by weight of the thermosetting resin. When the content of the aluminum hydroxide is less than 10 parts by weight, the total amount of heat emitted from the expanded molded body increases, and there is a risk of deterioration of thermal insulation properties, etc. .

(D) expanded graphite

Expanded graphite according to an embodiment of the present invention is applied to the thermosetting resin together with a hollow inorganic filler, and can improve flame retardancy, heat insulation, etc. of expandable polystyrene particles (expanded molded body) even with a small content.

In an embodiment, the expanded graphite may have an average particle diameter of 100 to 300 μm, for example, 150 to 250 μm, measured by LS 13 320 (Beckman Coulter).

In an embodiment, the expanded graphite may be included in an amount of 10 to 30 parts by weight, for example, 15 to 25 parts by weight, based on 100 parts by weight of the thermosetting resin. When the content of the expanded graphite is less than 10 parts by weight, there is a fear that the flame retardancy of the expandable polystyrene particles (expanded molded article) may decrease, and if it exceeds 30 parts by weight, the moldability of the expandable polystyrene particles may decrease.

(E) hollow inorganic filler

The hollow inorganic filler according to an embodiment of the present invention is applied to the thermosetting resin together with expanded graphite to improve the flame retardancy and heat insulation of expandable polystyrene particles (expanded molded body) even with a small content, and is generally used in resin compositions. Any hollow inorganic filler used may be used.

In an embodiment, the hollow inorganic filler may be a spherical hollow glass particle (glass bubble). Glass constituting the hollow glass particles includes silicon dioxide (SiO ₂ ), boron oxide (B ₂ O ₃ ), sodium oxide (Na ₂ O), calcium oxide (CaO), and the like soda-lime borosilicate glass (soda-lime). borosilicate glass) may be used, and one or two or more types of glass may be used.

In an embodiment, the hollow inorganic filler may have a specific gravity of 0.1 to 0.6, measured by LS 13 320 (Beckman Coulter) The average particle diameter may be 10 to 60 μm. In addition, the hollow inorganic filler may be surface-treated with a coupling agent or the like, but is not limited thereto.

In an embodiment, the hollow inorganic filler may be included in an amount of 6 to 20 parts by weight, for example, 8 to 16 parts by weight, based on 100 parts by weight of the thermosetting resin. When the content of the hollow inorganic filler is less than 6 parts by weight, there is a risk that the flame retardancy and thermal insulation properties of the expandable polystyrene particles (expanded molded article) may decrease, and if it exceeds 20 parts by weight, the moldability of the expandable polystyrene particles may decrease. there is

In an embodiment, the weight ratio (D:E) of the expanded graphite (D) and the hollow inorganic filler (E) may be 1:0.2 to 1:2, for example, 1:0.5 to 1:1.5. When the weight ratio of the expanded graphite and the hollow inorganic filler is less than 1:0.2, there is a risk that the thermal insulation properties of the expandable polystyrene particles (expanded molded article) may decrease, and when it exceeds 1:2, the moldability of the expandable polystyrene particles, etc. There is a risk of deterioration.

The coating composition for expandable polystyrene particles according to an embodiment of the present invention contains 40 to 100 parts by weight of a solvent, for example 50 to 80 parts by weight, based on 100 parts by weight of the thermosetting resin, in order to coat the coating composition on the particle surface. may be in the form of In the above range, it is possible to form a coating layer of a desired thickness.

In an embodiment, the solvent may be a conventional organic solvent used in the thermosetting resin coating composition, for example, isopropanol, ethanol, toluene, methyl ethyl ketone, etc. may be used.

In an embodiment, the coating composition for expandable polystyrene particles may be prepared by adding a thermosetting resin and a curing agent to a solvent and stirring, then adding aluminum hydroxide, expanded graphite and a hollow inorganic filler and stirring.

The expandable polystyrene particles according to the present invention are characterized in that the coating composition for expandable polystyrene particles is coated on the particle surface.

In an embodiment, the particles may be pre-expanded particles prepared by pre-foaming (heating to a softening point or higher) a conventional foamable resin composition. For example, the pre-foaming is performed by heating to 80 to 120° C., for example 90 to 110° C., using a heating medium such as steam, and a predetermined bulk density, for example, 10 to 35 kg/ m ³ , specifically 15 to 30 kg/m ³ may be foaming. In the above range, the balance of foamability and strength can be well maintained. The (pre-expanded) particles can be easily prepared by a person skilled in the art to which the present invention pertains.

In an embodiment, the foamable resin composition may be a conventional foamable resin composition, and may include, for example, a styrene-based resin and a foaming agent.

In an embodiment, the coating composition for expandable polystyrene particles may be coated in an amount of 100 to 300 parts by weight, for example, 150 to 250 parts by weight, based on 100 parts by weight of the particles. Within the above range, the expandable polystyrene particles (expanded molded article) may have excellent flame retardancy, heat insulation, moldability, strength, and the like.

In an embodiment, the coating of the expandable polystyrene particles is performed by adding the (pre-expanded) particles to the coating composition for expandable polystyrene particles and at 20 to 50° C., for example 25 to 40° C., for 5 to 10 minutes, for example 6 After stirring for 8 to 8 minutes, it can be obtained by drying.

The expanded molded article according to the present invention is formed by foaming the expandable polystyrene particles, and may be formed by, for example, filling a mold with the expandable polystyrene particles, heating and fusion bonding.

In an embodiment, the expanded molded article is formed by filling (introducing) the expandable polystyrene particles into a non-airtight mold, for example, under a pressure condition of 0.1 to 0.5 g/cm ² , hot air or water vapor at 110 to 120° C. It can be prepared by fusing the expandable polystyrene particles into a mold using

The expanded molded article may be easily manufactured by a person skilled in the art to which the present invention pertains.

In an embodiment, the expanded molded article may have a thermal conductivity of 0.03 to 0.038 W/m·K, for example, 0.033 to 0.036 W/m·K, measured according to ASTM C518.

In an embodiment, the foamed molded article may have a total amount of heat released according to KS F ISO 5660-1 of 2 to 8 MJ/m ² , for example 3 to 6 MJ/m ² .

Hereinafter, the present invention will be described in more detail through examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Example

Hereinafter, the specifications of each component used in Examples and Comparative Examples are as follows.

(A) thermosetting resin

(A1) A resol-type phenol resin (manufacturer: Sun Synthesis, product name: PA-400) was used.

(A2) Melamine resin (manufacturer: Sun Synthesis, product name: M80S) was used.

(A3) An epoxy resin (manufacturer: Struder, product name: EpoFix Resin) was used.

(B) curing agent

Dodecyl benzyl sulfonic acid (manufacturer: Aldrich) was used.

(C) flame retardant

(C1) Aluminum hydroxide (manufacturer: Daejung Chemical) was used.

(C2) Calcium hydroxide (Manufacturer: Daejung Hwageum)

(D) insulation

(D1) Expanded graphite (manufacturer: hydraulic chemical, product name: ADT-802B) was used.

(D2) Diatomaceous earth (manufacturer: HAYASHI KASEI, product name: Radiolite N200) was used.

(E) hollow inorganic filler

Hollow glass particles (manufacturer: 3M, product name: K1) were used.

Example 1 to 5 and comparative example 1 to 12

According to the contents of Tables 2, 3 and 4 below, (A) thermosetting resin and (B) curing agent are added to isopropanol and stirred, and then (C) flame retardant, (D) heat insulating agent and/or (E) hollow inorganic Filler was added and stirred to prepare a coating composition.

Next, expandable polystyrene (pre-expanded) particles (manufacturer: Lotte Advanced Materials, product name: Starex SG201) were added to the prepared coating composition, stirred at 25° C. for 6 minutes, and dried, the coating composition coated expandable polystyrene Particles (based on 100 parts by weight of the particles, coated with 150 to 250 parts by weight of the coating composition) were prepared.

The prepared expandable polystyrene particles are filled (introduced) into a non-airtight mold, put into a steam molding machine, and the expandable polystyrene particles are fuse in the mold at a pressure of 0.4 g/cm ² and a temperature of 120° C. for 15 minutes to produce an expanded molded article Then, it was dried at 60° C. for 12 hours, and cut with a hot wire to prepare a specimen. For the prepared specimen, thermal conductivity and flame retardancy were evaluated by the following physical property measurement method, and the results are shown in Tables 2, 3 and 4 below.

How to measure physical properties

(1) Thermal conductivity (unit: W/m·K): According to ASTM C518, thermal conductivity ( Unit: W/m·K) was measured.

(2) Flame-retardant evaluation: In accordance with KS F ISO 5660-1, the total amount of heat released (unit: MJ/m ² ) of the expanded molded article having a size of 10 cm × 10 cm × 3 cm was measured.

(3) Formability evaluation: In each Example and Comparative Example, after steam forming, after drying at 60° C. for 12 hours, at 25° C. and 50% humidity conditions, (1) the degree of visible gaps between particles, (2) The degree to which the shape of each particle maintains the spherical shape, and (3) the degree of separation without breaking the particles due to poor adhesion properties were evaluated by visually checking. The evaluation criteria are shown in Table 1 below.

◎ ○ × No deformation or cracks,
Excellent adhesion between particles There is no deformation or cracking,
Lack of adhesion between particles Deformation and cracking

Example One 2 3 4 5 (A) (wt%) (A1) 60 80 90 80 80 (A2) 40 20 10 20 20 (A3) - - - - - (B) (parts by weight) 1.0 0.8 0.8 0.8 0.8 (C) (parts by weight) (C1) 40 40 40 40 40 (C2) - - - - - (D) (parts by weight) (D1) 15 15 15 10 30 (D2) - - - - - (E) (parts by weight) 10 10 10 20 6 (D):(E) (weight ratio) 1:0.7 1:0.7 1:0.7 1:2 1:0.2 Thermal conductivity (W/m·K) 0.034 0.034 0.034 0.033 0.036 Total heat released (MJ/m ² ) 6 4 4 6 3 formability ◎ ◎ ◎ ◎ ○

comparative example One 2 3 4 5 (A) (wt%) (A1) 40 95 80 - 80 (A2) 60 5 - 30 20 (A3) - - 20 70 - (B) (parts by weight) 1.0 0.8 0.8 0.8 0.8 (C) (parts by weight) (C1) 40 40 40 40 - (C2) - - - - 40 (D) (parts by weight) (D1) 15 15 15 15 15 (D2) - - - - - (E) (parts by weight) 10 10 10 10 10 (D):(E) (weight ratio) 1:0.7 1:0.7 1:0.7 1:0.7 1:0.7 Thermal conductivity (W/m·K) 0.035 0.035 0.038 0.040 0.045 Total heat released (MJ/m ² ) 11 3 10 15 4 formability ◎ × × × ×

comparative example 6 7 8 9 10 11 12 (A) (wt%) (A1) 80 80 80 - 80 80 80 (A2) 20 20 - 30 20 20 20 (A3) - - 20 70 - - - (B) (parts by weight) 0.8 0.8 0.8 0.8 0.8 0.8 0.8 (C) (parts by weight) (C1) 40 40 40 40 40 - 40 (C2) - - - - - 40 - (D) (parts by weight) (D1) 5 50 - 15 30 15 5 (D2) - - 15 - - - 10 (E) (parts by weight) 10 10 10 2 30 2 40 (D):(E) (weight ratio) 1:2 1:0.2 1:0.7 1:0.13 1:1 1:0.13 1:2.67 Thermal conductivity (W/m·K) 0.032 0.045 0.040 0.042 0.032 0.038 0.036 Total heat released (MJ/m ² ) 14 3 15 15 3 10 5 formability ◎ × × × × ○ ×

From the above results, it can be seen that the expanded molded article formed from expandable polystyrene particles to which the coating composition of the present invention is applied has excellent flame retardancy (total heat released), heat insulation (thermal conductivity), and the like.

On the other hand, in the case of Comparative Example 1 in which a small amount of a phenol resin is applied and an excessive amount of melamine resin is applied, it can be seen that the flame retardancy is lowered, and in the case of Comparative Example 2 in which an excessive amount of the phenol resin is applied and a small amount of the melamine resin is applied, moldability, etc. It can be seen that this decreases. In the case of Comparative Example 3 in which an epoxy resin (A3) is applied instead of a melamine resin, it can be seen that flame retardancy, moldability, etc. are lowered, and in Comparative Example 4 in which an epoxy resin (A3) is applied instead of a phenol resin, heat insulation, flame retardancy, It can be seen that the formability is deteriorated, and in the case of Comparative Example 5 in which calcium hydroxide (C2) is applied instead of aluminum hydroxide, it can be seen that the thermal insulation properties, the formability, etc. are reduced. In the case of Comparative Example 6 in which a small amount of expanded graphite is applied, it can be seen that the flame retardancy is lowered, and in the case of Comparative Example 7 in which an excessive amount of expanded graphite is applied, it can be seen that thermal insulation properties, formability, etc. are reduced, and diatomaceous earth (D2) instead of expanded graphite ), in the case of Comparative Example 8, it can be seen that the heat insulation, flame retardancy, moldability, etc. are lowered. In the case of Comparative Example 9 in which a small amount of the hollow inorganic filler was applied, it can be seen that heat insulation, flame retardancy, moldability, etc. are reduced, and in Comparative Example 10 in which an excessive amount of the hollow inorganic filler is applied, it can be seen that the moldability is reduced. In addition, even if the content of expanded graphite and/or hollow inorganic filler is included in the scope of the present invention, when the weight ratio is less than the scope of the present invention (Comparative Example 11), it can be seen that heat insulation, flame retardancy, etc. are lowered, and the weight ratio is the present invention If it exceeds the range of (Comparative Example 12), it can be seen that the moldability and the like are lowered.

Simple modifications or changes of the present invention can be easily carried out by those of ordinary skill in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (11)

100 parts by weight of a thermosetting resin comprising 60 to 90% by weight of a phenol resin and 10 to 40% by weight of a melamine resin;
0.5 to 2 parts by weight of a curing agent;
10 to 50 parts by weight of aluminum hydroxide;
10 to 30 parts by weight of expanded graphite; and
6 to 20 parts by weight of the hollow inorganic filler;
The curing agent includes at least one of dodecylbenzenesulfonic acid, sulfuric acid, phosphoric acid, benzenesulfonic acid, ethylbenzenesulfonic acid, paratoluenesulfonic acid, xylenesulfonic acid, and naphtholsulfonic acid,
The coating composition for expandable polystyrene particles, characterized in that the weight ratio of the expanded graphite and the hollow inorganic filler is 1:0.2 to 1:2.
The coating composition for expandable polystyrene particles according to claim 1, wherein the coating composition for expandable polystyrene particles comprises 40 to 100 parts by weight of a solvent based on 100 parts by weight of the thermosetting resin.
The coating composition for expandable polystyrene particles according to claim 1, wherein the phenol resin is a resol-type phenol resin.
delete The coating composition for expandable polystyrene particles according to claim 1, wherein the hollow inorganic filler is a spherical hollow glass particle.
[Claim 6] Expandable polystyrene particles, characterized in that the coating composition for expandable polystyrene particles according to any one of claims 1 to 3 and 5 is coated on the particle surface.
The expandable polystyrene particles according to claim 6, wherein the particles are pre-foamed with a foamable resin composition to a density of 10 to 35 kg/m ³ .
The expandable polystyrene particles according to claim 7, wherein the expandable resin composition comprises a styrene-based resin and a foaming agent.
An expanded molded article, characterized in that it is formed by filling a mold with the expandable polystyrene particles according to claim 6, heating, and fusion.
10. The foamed molded article according to claim 9, wherein the expanded molded article has a thermal conductivity of 0.03 to 0.038 W/m·K, measured in accordance with ASTM C518.
[10] The foamed molded article according to claim 9, wherein the foamed molded article has a total amount of heat emitted measured in accordance with KS F ISO 5660-1 of 2 to 8 MJ/m ² .