Polyester resin composition, and paint composition comprising polyester resin prepared therefrom

Abstract

The present invention provides an eco-friendly polyester resin composition capable of minimizing the emission of carbon dioxide, and a paint composition comprising a polyester resin prepared therefrom.

Description

Polyester resin composition and paint composition comprising a polyester resin prepared therefrom

[0001] The present invention relates to an environmentally friendly polyester resin composition and a paint composition comprising a polyester resin produced therefrom.

[0002]

[0003] Pre-Coated Metal (PCM) is metal coated with paint and then processed. It is used in a variety of applications, including home appliances and building materials. Therefore, paints for PCM (Pre-Coated Metal) must have excellent processability, and depending on the application, additional properties such as excellent hardness, scratch resistance, and weather resistance are required. Various PCM paints are used, including acrylic, urethane, epoxy, polyester, silicone, fluorine, and polyvinyl chloride. However, polyester paint compositions, due to their excellent processability, are the most commonly used. Research and development are actively being conducted to improve the properties of such polyester paint compositions, and as an example, Korean Patent Publication No. 10-2001-0048577 discloses a polyester resin composition obtained by condensing a glycol compound containing bisphenol A, bisphenol F and / or bisphenol S having a hydroxy equivalent of 100 to 400 and an aromatic acid-containing diacid compound, to which ethylene oxide or propylene oxide is added.

[0004] However, conventional polyester paint compositions are manufactured using resins, monomers, and solvents derived from fossil fuels like petroleum and coal. This inevitably leads to the production of carbon dioxide, a contributor to global warming. Therefore, the development of environmentally friendly polyester paint compositions that can minimize carbon dioxide emissions is urgently needed.

[0005]

[0006] The present invention provides an environmentally friendly polyester resin composition capable of minimizing carbon dioxide emissions and a paint composition comprising a polyester resin manufactured therefrom.

[0007]

[0008] The present invention provides a polyester resin composition comprising an acid monomer and an alcohol monomer, wherein at least one of the acid monomer and the alcohol monomer is a bio-based monomer, and a polyester resin produced from the polyester resin composition has a bio content of 20 wt% or more, and a paint composition comprising a polyester resin produced therefrom.

[0009]

[0010] The present invention provides an environmentally friendly polyester resin composition capable of minimizing carbon dioxide emissions and a paint composition comprising a polyester resin manufactured therefrom. The polyester resin composition of the present invention and the paint composition comprising the polyester resin manufactured therefrom are environmentally friendly and exhibit physical properties equivalent to or higher than those of conventional fossil fuel-based polyester resins and paint compositions comprising the same. The polyester resin composition of the present invention and the paint composition comprising the polyester resin manufactured therefrom have a high bio-content and are thus applicable to various industrial fields requiring a high bio-content.

[0011]

[0012] The present invention will be described in detail below. However, it is not limited to the following description, and each component may be modified or selectively mixed as needed. Therefore, it should be understood that all modifications, equivalents, and alternatives included within the spirit and technical scope of the present invention are included.

[0013] The “weight average molecular weight” used herein is measured by a conventional method known in the art, and can be measured, for example, by a gel permeation chromatography (GPC) method. The “glass transition temperature” is measured by a conventional method known in the art, and can be measured, for example, by a differential scanning calorimetry (DSC) method. The functional group such as the “hydroxyl value” is measured by a conventional method known in the art, and can be measured, for example, by a titration method.

[0014]

[0015] <Polyester resin composition>

[0016] The polyester resin composition of the present invention comprises an acid monomer and an alcohol monomer.

[0017] The acid monomer may be an aliphatic acid, an aromatic acid, or a mixture thereof. For example, isophthalic acid, terephthalic acid, adipic acid, trimellitic anhydride, dimer acid, sebacic acid, succinic acid, phthalic anhydride, benzene tricarboxylic acid anhydride, naphthalene tricarboxylic acid anhydride, etc. may be used, and these may be used alone or in combination of two or more. For example, the acid monomer may include at least one selected from the group consisting of isophthalic acid, terephthalic acid, adipic acid, trimellitic anhydride, and dimer acid. In this case, as the number of ester bonds in the polyester resin increases, the weight average molecular weight of the polyester resin can be further increased, and when applied to a paint, the adhesion, processability, and storability can be further improved.

[0018] The alcohol monomer may be a polyfunctional alcohol, and may be an aliphatic alcohol, an aromatic alcohol, or a mixture thereof. For example, ethylene glycol, propylene glycol, 1,2-butylene glycol, neopentyl glycol, 1,6-hexanediol, trimethylol propane, glycerol, bisphenol A (BPA), an alkoxylated alcohol, propanediol, isosorbide, etc. may be used, and these may be used alone or in combination of two or more. For example, the alcohol monomer may include at least one selected from the group consisting of ethylene glycol, neopentyl glycol, and ethoxylated bisphenol A. In this case, the price competitiveness, reactivity and hardness of the polyester resin can be further improved.

[0019] At least one of the above acid monomers and alcohol monomers is a bio-based monomer. The bio-based acid monomer and / or bio-based alcohol monomer is derived from plants such as rapeseed oil, castor oil, and corn oil, and can reduce carbon dioxide emissions, unlike conventional polyester resins manufactured using acid monomers and alcohol monomers manufactured from fossil fuels.

[0020] For example, the bio-based acid monomer may include at least one selected from the group consisting of bio-based dimer acid, bio-based sebacic acid, bio-based succinic acid, and bio-based azelaic acid. For example, the bio-based alcohol monomer may include at least one selected from the group consisting of bio-based propanediol, bio-based isosorbide, and bio-based dimer alcohol.

[0021] The above bio-based acid monomer may be included in an amount of 20 to 45 wt%, for example, 25 to 35 wt%, based on the total weight of the polyester resin composition. If the content of the bio-based acid monomer is less than the above-mentioned range, processability may be reduced during paint production, and resin storability may be poor, resulting in cracking. If the content exceeds the above-mentioned range, corrosion resistance may be reduced, tackiness may be strong, curing may be reduced, and paint foaming may be poor.

[0022] The above bio-based alcohol monomer may be included in an amount of 20 to 25 wt% based on the total weight of the polyester resin composition. If the content of the bio-based alcohol monomer is less than the above-mentioned range, processability may be reduced during paint production, resin storability may be poor, resulting in haziness over time, and solvent compatibility may be reduced. If the content exceeds the above-mentioned range, corrosion resistance may be reduced, and curing degree, alkali resistance, and paint defoaming may be poor.

[0023] The above polyester resin composition may further include a solvent. This can enhance the solubility and lower the viscosity of the composition, thereby improving workability. Any solvent commonly used in the relevant technical field can be used without particular limitation, including solvent naphtha, cyclohexanone, xylene, and the like.

[0024] The polyester resin composition may include 20 to 45 wt% of the acid monomer, 5 to 25 wt% of the alcohol monomer, and 45 to 55 wt% of the solvent, based on the total weight of the polyester resin composition.

[0025] The total content of the bio-based monomer in the polyester resin composition, i.e., the bio content of the polyester resin manufactured from the polyester resin composition, may be 20 wt% or more, for example, 30 to 50 wt%, or as another example, 35 to 45 wt%. If the bio content is less than the above-mentioned range, carbon dioxide emissions may increase, which may be unfriendly to the environment, and if it exceeds the above-mentioned range, the strength and hardness of the coating film may decrease, which may deteriorate the physical properties of the coating film. The coating composition of the present invention is environmentally friendly and can be applied to various industrial fields requiring a high bio content by using a polyester resin with a high bio content.

[0026] The bio-content can be calculated as the proportion of radioactive carbon (C14) in the total carbon content. Biomass materials contain radioactive carbon (C14), a carbon isotope, whereas petrochemical-derived materials do not. Therefore, the bio-content can be calculated by calculating the proportion of C14 in the total carbon content.

[0027] The weight average molecular weight of the polyester resin manufactured from the polyester resin composition may be 3,000 to 10,000 g / mol, for example, 5,500 to 7,500 g / mol. If the weight average molecular weight of the polyester resin is less than the above-mentioned range, the molecular weight may be small, which may deteriorate the basic physical properties of the coating film, such as processability, hardness, corrosion resistance, and adhesion, and if it exceeds the above-mentioned range, the content of the solvent added for viscosity control may increase, making it difficult to form a coating film of a predetermined thickness, and compatibility with other resins or additives may deteriorate.

[0028] The glass transition temperature of the polyester resin manufactured from the polyester resin composition may be 1 to 20°C, for example, 5 to 10°C. If the glass transition temperature of the polyester resin is less than the above-mentioned range, the flexibility of the resin increases, but the glass transition temperature of the coating film may decrease, resulting in deterioration of chemical resistance, corrosion resistance, and hardness. If the glass transition temperature exceeds the above-mentioned range, the flexibility of the resin may decrease, the glass transition temperature of the coating film may increase, resulting in deterioration of processability.

[0029] The hydroxyl value of the polyester resin manufactured from the polyester resin composition may be 15 to 55 KOHmg / g, for example, 25 to 35 KOHmg / g. If the hydroxyl value of the polyester resin is less than the above-mentioned range, the bonding strength may be reduced due to a lack of OH groups in the resin, which may result in reduced water resistance and curing properties. If the hydroxyl value exceeds the above-mentioned range, OH groups may remain in the paint, which may result in excessive bonding within the paint, which may result in reduced processability and moldability.

[0030] The acid value of the polyester resin prepared from the polyester resin composition may be 5 KOHmg / g or less, for example, 1 to 5 KOHmg / g. If the acid value of the polyester resin is less than the above-mentioned range, the reaction time may be prolonged, which may result in a deterioration in the color and appearance of the resin. If the acid value exceeds the above-mentioned range, the basic physical properties of the paint, such as processability, corrosion resistance, and hardness, may be deteriorated due to failure to reach an appropriate molecular weight.

[0031] The viscosity (25°C) of the polyester resin prepared from the polyester resin composition may be 2,000 to 7,000 mPas, for example, 2,500 to 5,500 mPas. If the viscosity of the polyester resin is less than the above-mentioned range, the molecular weight of the resin may decrease, resulting in deterioration in processability, corrosion resistance, hardness, etc., and if it exceeds the above-mentioned range, the storability and compatibility of the resin may decrease.

[0032] The solids content of the polyester resin manufactured from the polyester resin composition may be 40 to 70%, for example, 49 to 51%. If the solids content of the polyester resin is less than the aforementioned range, the resin viscosity may be too low to meet the target viscosity of the paint, and if it exceeds the aforementioned range, the resin viscosity may be too high, resulting in poor workability.

[0033]

[0034] <Paint composition>

[0035] The paint composition according to the present invention comprises a polyester resin prepared from the aforementioned polyester resin composition. The paint composition of the present invention is environmentally friendly due to its high bio-content, and is applicable to various industrial fields requiring high bio-content.

[0036] Additionally, the paint composition according to the present invention may further include pigments, solvents, curing accelerators, and additives commonly used in the relevant technical fields, as needed. Non-limiting examples of additives usable in the present invention include leveling agents, plasticizers, anti-settling agents, waxes, light stabilizers, gloss regulators, and the like.

[0037]

[0038] The present invention will be described in more detail through the following examples. However, the following examples are intended only to aid understanding of the present invention and are not intended to limit the scope of the present invention in any way.

[0039]

[0040] [Synthesis Example 1]

[0041] In a glass flask equipped with a stirrer, condenser, nitrogen injection device, temperature controller, and thermometer, 70 g of ethylene glycol, 50.6 g of neopentyl glycol, 33.1 g of ethoxylated bisphenol A, 4.5 g of trimethylolpropane, 102.1 g of terephthalic acid, 100 g of isophthalic acid, 3 g of trimellitic anhydride, and 0.1 g of catalyst (butylchlorodihydroxytin) were added, and esterification was performed at 250 °C and 200 rpm for 2 hours. When the acid value was measured to be 10 mgKOH / g or less, the mixture was cooled to 150 °C or lower, 210 g of bio-based acid monomer (Dimer acid, Cargill's Pripol 1009) was added, and esterification was performed at 250 °C and 200 rpm for 2 hours. When the acid value was measured to be 20 mgKOH / g or less, the mixture was cooled to 150°C or less, 20 g of xylene was added, and after refluxing at 230°C and 200 rpm, when the acid value became 5 mgKOH / g or less, the mixture was diluted with a solvent to produce a polyester resin of Synthesis Example 1. The physical properties of the produced polyester resin are shown in Table 1.

[0042]

[0043] [Synthesis Example 2-9]

[0044] Polyester resins of Synthetic Examples 2 to 9 were manufactured in the same manner as Synthetic Example 1, except that the compositions were as shown in Table 1 below.

[0045]

[0046]

[0047]

[0048] [Experimental Example 1-9: Preparation of Paint Composition]

[0049] According to Table 2 below, the paint composition for each experimental example was prepared.

[0050]

[0051]

[0052]

[0053] Polyester 1: Polyester resin of Synthesis Example 1

[0054] Polyester 2: Polyester resin of Synthesis Example 2

[0055] Polyester 3: Polyester resin of Synthetic Example 3

[0056] Polyester 4: Polyester resin of Synthetic Example 4

[0057] Polyester 5: Polyester resin of Synthetic Example 5

[0058] Polyester 6: Polyester resin of Synthetic Example 6

[0059] Polyester 7: Polyester resin of Synthetic Example 7

[0060] Polyester 8: Polyester resin of synthetic example 8

[0061] Polyester 9: Polyester resin of Synthetic Example 9

[0062] Auxiliary resin: polyester resin (Mw 3,300 g / mol, Ohv 61 KOHmg / g, Tg 13 ℃, NV 60%, viscosity (25 ℃) 600-1,000 cps)

[0063] Melamine: Methylated melamine resin (ACM00167)

[0064] Solvent 1: Dibasic ester (ADD00198)

[0065] Solvent 2: Propylene glycol methyl ether acetate (AAF00305)

[0066] Solvent 3: Solvent naphtha (petroleum), light arom (AAB11161)

[0067] Additive 1: Silicone-based defoaming agent (AEN01377)

[0068] Additive 2: Matting agent (Silicon dioxide)

[0069] Catalyst: Sulfonic acid

[0070]

[0071] [Physical property evaluation]

[0072] The properties of the paint composition manufactured according to each experimental example were measured using the following method, and the results are shown in Table 3 below.

[0073]

[0074] Sample manufacturing

[0075] The paint composition of each experimental example was coated on a GI steel plate for PCM (thickness: 5 to 15 ㎛) and cured by heating and drying (PMT 232 ℃) to prepare a specimen.

[0076]

[0077] WET exterior

[0078] Each specimen was visually observed for defects such as swelling, peeling, surface cracks, pinholes, bubbles, and foreign matter, and the appearance was evaluated according to the following criteria.

[0079] [metewand]

[0080] Excellent (◎): No defects (surface cracks, bubbles, etc.)

[0081] Defective (X): Occurrence of defects (surface cracks, bubbles, etc.)

[0082]

[0083] Vesicular

[0084] The paint composition of each experimental example was divided into 300 g portions and stirred at 1,500 rpm for 30 seconds. Then, the presence of bubbles was observed and compared relative to each other to evaluate them as excellent (◎), good (○), average (△), or poor (Х).

[0085]

[0086] gloss

[0087] Using a gloss meter, the gloss of each specimen surface was measured at a measurement angle of 60° and evaluated as excellent (◎), good (○), average (△), or poor (Х) through relative comparison.

[0088]

[0089] Processability

[0090] According to ASTM D4145, each specimen was tested by bending (0T, 1T, 2T) and clamping it in a vice. Then, the processability was evaluated by checking for cracks in the processed area using a 15x magnifying glass.

[0091] [metewand]

[0092] Very good: 0T NO CRACK

[0093] Excellent: 0T points CRACK

[0094] Normal: 0T CRACK

[0095] Micro-disadvantage: 1T point CRACK

[0096] Defect: 1T CRACK

[0097]

[0098] Hardening (MEK Rubbing)

[0099] After wetting the gauze with the solvent (MEK), the surface of each specimen was rubbed with a 1 kg load, and the surface condition was compared relative to each other and evaluated as excellent (◎), good (○), average (△), or poor (Х).

[0100]

[0101] Korean department store

[0102] After storing each specimen at 0℃ for 1 hour, each specimen was bent (0T, 1T, 2T) and fixed in a vice according to ASTM D4145, and the presence of cracks in the processed area was observed using a 15x magnifying glass and evaluated as excellent (◎), good (○), average (△), or poor (Х) through relative comparison.

[0103]

[0104] Chemical resistance

[0105] After immersing each specimen in 5% NaOH and 5% CH3COOH for 24 hours, the appearance of the coating was visually observed and evaluated according to the ASTM D714-87 standard.

[0106]

[0107]

[0108]

[0109] As can be seen from the results in Table 2 above, the paint composition of Experimental Example 1-5 using the polyester resin (Synthesis Example 1-5) according to the present invention exhibited excellent physical properties across all measured items. In particular, despite the use of an eco-friendly bio-based polyester resin, it exhibited similar physical properties to the paint composition of Experimental Example 9 using a petrochemical-based polyester resin (Synthesis Example 9). On the other hand, the paint composition of Experimental Example 6-8 using a polyester resin (Synthesis Example 6-8) outside the bio-content range according to the present invention exhibited generally inferior physical properties compared to the paint composition of Experimental Example 1-5.

[0110]

[0111] The present invention provides an environmentally friendly polyester resin composition capable of minimizing carbon dioxide emissions and a paint composition comprising a polyester resin manufactured therefrom.

Claims

1. A polyester resin composition comprising an acid monomer and an alcohol monomer, At least one of the above acid monomers and the above alcohol monomers is a bio-based monomer, A bio-polyester resin composition comprising a polyester resin prepared from the above polyester resin composition having a bio content of 20 wt% or more.

2. In the first paragraph, the acid monomer is a polyester resin composition comprising at least one selected from the group consisting of isophthalic acid, terephthalic acid, adipic acid, trimellitic anhydride, and dimer acid.

3. A polyester resin composition according to claim 1, wherein the alcohol monomer comprises at least one selected from the group consisting of ethylene glycol, neopentyl glycol, and ethoxylated bisphenol A.

4. In the first paragraph, the acid monomer is a bio-based monomer, A polyester resin composition comprising at least one bio-based acid monomer selected from the group consisting of bio-based dimer acid, bio-based sebacic acid, bio-based succinic acid, and bio-based azelaic acid.

5. In the first paragraph, the alcohol monomer is a bio-based monomer, A polyester resin composition comprising at least one bio-based alcohol monomer selected from the group consisting of bio-based propanediol, bio-based isosorbide, and bio-based dimer alcohol.

6. In the fourth paragraph, the bio-based acid monomer is contained in a polyester resin in an amount of 20 to 45 wt% based on the total weight of the polyester resin composition.

7. In the fifth paragraph, the bio-based alcohol monomer is contained in a polyester resin in an amount of 20 to 25 wt% based on the total weight of the polyester resin composition.

8. A polyester resin composition in which the weight average molecular weight of the polyester resin prepared from the polyester resin composition in paragraph 1 is 3,000 to 10,000 g / mol, the glass transition temperature is 1 to 20°C, the hydroxyl value is 15 to 55 KOHmg / g, the acid value is 5 KOHmg / g or less, the viscosity (25°C) is 2,000 to 7,000 mPas, and the solid content is 40 to 70%.

9. A paint composition comprising a polyester resin prepared from the polyester resin composition of any one of claims 1 to 8.

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