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Article
Publication date: 6 July 2010

S. Awasthi and D. Agarwal

The purpose of this paper is to describe how to synthesise polyurethane resins by using different polyester polyols and HDI isocyanurate. The polyester polyols were…

Abstract

Purpose

The purpose of this paper is to describe how to synthesise polyurethane resins by using different polyester polyols and HDI isocyanurate. The polyester polyols were prepared by reacting single diol with different diacids. The effects of these polyester polyols on the performance properties of the coating films are studied.

Design/methodology/approach

A series of hydroxyl‐terminated polyester polyols were synthesised by using 1,4‐cyclohexanedimethanol (1,4‐CHDM) with different diacids such as 1,3‐cyclohexanedicarboxylic acid (1,3‐CHDA), 1,4‐CHDA, adipic acid (AA), azelaic acid (AZA), and isophthalic acid (IPA). The general properties including acid number, hydroxyl number average molecular weight, polydispersity index, and viscosity of these polyester polyols were evaluated. Different coating formulations were developed by using polyester polyols and HDI isocyanurate. These coatings were applied on sand blasted mild steel panels and glass panels and were cured in hot air oven. Various mechanical, thermal and chemical resistance properties of the coating films were evaluated.

Findings

The paper shows that, the polyurethane coatings have good resistance to water and other chemicals and can be used safely in exterior applications. In polyester polyols for polyurethane coating, CHDA showed a good balance in mechanical properties, which may be attributed to its unique cycloaliphatic structure and 1,4‐substitution. The polyester polyol based on aromatic diacids provided polyurethane coatings with maximum hardness and high Tg.

Research limitations/implications

The polyurethane resins were prepared from polyester polyol (made up of cyclohexanedimethanol (CHDM) and CHDA, IPA, AA, and AZA). Besides, this, it can be synthesised from some other polyester polyols (having different acids and alcohols) or polyether polyols. In addition to this, some other isocyanates such as TDI, MDI, HMDI, etc. can also be used.

Practical implications

The paper has provided a better solution for developing high solid polyurethane coatings for exterior applications due to presence of cycloaliphatic compounds.

Originality/value

In this paper, cyclohexyl dibasic acids have been used as the replacement for the aromatic dibasic acids. In aromatic dibasic acids, the phenyl ring readily absorbs UV‐light limiting the photo‐oxidative stability of the polyesters. So, these studies will help to develop high‐solid polyurethane coatings which could find numerous industrial applications in surface coatings.

Details

Pigment & Resin Technology, vol. 39 no. 4
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 29 June 2012

A.P. Kabra, P. Mahanwar, V. Shertukde and V. Bambole

The purpose of this paper is to formulate two component polyurethane coatings based on acrylic polyol, to study the effects of variable nanosilica loadings in these…

Abstract

Purpose

The purpose of this paper is to formulate two component polyurethane coatings based on acrylic polyol, to study the effects of variable nanosilica loadings in these coatings on different morphological, optical, mechanical, corrosion resistance and weather resistance properties and to study the intercalation of acrylic polyol molecules into nanosilica crystals by XRD technique.

Design/methodology/approach

Two component polyurethane coatings were synthesised using acrylic polyol and isocyanate HDI. The nanosilica was incorporated in polyurethane formulation at the weight ratios of 1%, 3% and 5% based on total weight of polyol and isocyanate. The performance of nanocoatings was compared for variable loads of nanosilica for different properties such as morphological, optical, mechanical, corrosion resistance, weather resistance and were studied for intercalation of acrylic polyol into nanosilica crystals by XRD technique.

Findings

Improvement in the properties of polyurethane coatings is achieved with the incorporation of nanosilica. The improvement is the result of inherently high properties of inorganic nanosilica. Tensile strength, scratch hardness, abrasion resistance, corrosion and weathering resistance show significant improvement in performance with the incorporation of nanosilica. Properties are found to deteriorate beyond a certain loading of nanosilica; hence it is important to optimise loading level. The optimal range for high performance was found to be in the range of 1% to 3%. The improvement was a result of synergistic behaviour and good interfacial interaction between polyurethane and nanosilica at optimal levels.

Research limitations/implications

The method used for incorporation of nanosilica into polyurethane was direct incorporation method. The other method of incorporation, i.e. in situ addition and its effect on properties can also be studied.

Practical implications

With the addition of optimal loading level of nanosilica to polyurethane coatings, properties can be enhanced up to the mark. The addition is relatively easy and cost effective.

Originality/value

The paper proves the significance of incorporation of nanosilica on original properties of polyurethane coatings and widens the area of applications of two component polyurethane coatings from acrylic polyol by strengthening them in their properties. The coatings can be applicable in high performance topcoats especially for automotive topcoats.

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Article
Publication date: 7 November 2016

Tingting Xu, Cuifeng Zhang and Lijun Chen

Presently, a wide range of polyurethane adhesives can be obtained using different kinds of polyols and isocyanates. However, the applied temperature of the polyurethane…

Abstract

Purpose

Presently, a wide range of polyurethane adhesives can be obtained using different kinds of polyols and isocyanates. However, the applied temperature of the polyurethane adhesive is not more than 80°C. The film of polyurethane adhesive will be softened and deformed when its applied temperature is more than 100°C. Thus, the mechanical property of the polyurethane adhesive is decreased clearly, which limits its further application. The purpose of the study is to improve the heat resistance of polyols, especially polyester polyols and its resultant polyurethane adhesives.

Design/methodology/approach

The more rigid benzene ring is introduced into the polyester polyols to improve the heat resistance of its resultant polyurethane adhesive.

Findings

The more rigid benzene ring has ben introduced into the polyester polyols and the heat resistance of its resultant polyurethane adhesive is improved.

Originality/value

The polyester polyols with more rigid benzene ring have been prepared successfully by the vacuum melting method when diethylene glycol, neopentyl glycol, 1,6-hexanediol, ethanediol, isophthalic acid, terephthalic acid, sebacic acid and adipic acid are used as raw materials and tetra-isopropyl titanate is adopted as the catalyst.

Details

Pigment & Resin Technology, vol. 45 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 5 March 2018

Aarti P. More and Shashank T. Mhaske

The study aims to synthesise polyurethane dispersion from polyesteramide polyol. The polyesteramide polyol is a novel polyol for the synthesis of polyurethane dispersion.

Abstract

Purpose

The study aims to synthesise polyurethane dispersion from polyesteramide polyol. The polyesteramide polyol is a novel polyol for the synthesis of polyurethane dispersion.

Design/methodology/approach

Polyesteramide polyol has been synthesised from phthalic anhydride and fatty amide of mustard oil. Aminolysis of mustard oil had been carried out with diethanolamine. The novel polyurethane dispersion had been synthesised using a polyesteramide polyol as a precursor. Isophorone diisocyanate was used as an isocyanate component and polyurethane dispersion (PUDs) had been synthesised by an anionic method where DMPA was introduced to introduce –COOH groups as via grafting to the resin backbone. Triethylamine was used for neutralisation and, hence, for further dispersion in water. Hydroxyl ethyl methacrylate was used for the synthesis to introduce unsaturation in the backbone of PUDs. The coating was made by an UV curing process. The coating was characterised for mechanical properties, chemical properties, thermal properties as well as stain resistance.

Findings

The polyurethane dispersion formed through it has ester and amide linkage present in it. The acetone process is used for its synthesis. The nuclear magnetic resonance spectroscopy confirms the successful formation of polyesteramide polyol and PUDs. Even though long aliphatic chains present in polyol which may impart hydrophobicity the synthesis PUDs well dispersed in water. It is observed as the coating made from it have hardness and scratch resistance properties. The coating also exhibits good stain resistance properties.

Practical implications

The method is an easy one to synthesise polyurethane dispersion from polyesteramide polyol, which is based on ester and amide linkage.

Originality/value

To the best of the authors’ knowledge, this is the first report on synthesised polyurethane dispersion from polyesteramide polyol. The polyesteramide resin already proves its excellence and upcoming technology in the coating industry. Here, they are incorporated into the synthesis of polyurethane dispersion.

Details

Pigment & Resin Technology, vol. 47 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

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Article
Publication date: 3 February 2021

Abbas Ahmad Adamu, Norazilawati Muhamad Sarih and Seng Neon Gan

Poly(ethylene terephthalate) (PET) waste from soft drink bottles was incorporated into palm olein alkyd to produce new polyol for use in polyurethane resins as surface…

Abstract

Purpose

Poly(ethylene terephthalate) (PET) waste from soft drink bottles was incorporated into palm olein alkyd to produce new polyol for use in polyurethane resins as surface protection on metal surfaces.

Design/methodology/approach

Alkyd was prepared from palm olein, glycerol and phthalic anhydride. PET underwent simultaneous glycolysis and transesterification reactions with the alkyd. Varying the amount of PET has led to polyols with different viscosities. Polyurethane resins were produced by reacting the polyols with toluene diisocyanate. The resins were coated on mild steel panels and cured. Performances of the cured films were tested.

Findings

The polyurethanes (PU) resin cured to a harder film with better thermal stability. Films showed excellent adhesion properties, while higher content of PET exhibited higher pencil hardness, better water, salt, acid and alkali resistance.

Research limitations/implications

Other vegetable oils could also be used. The alkyd structure could be changed by formulation to have different functionality and the ability to incorporate higher amount of PET waste. Rate of glycolysis of PET could be increased by higher amount of ethylene glycol.

Practical implications

This method has managed to use waste PET in producing new polyol and PU resins. The cured films exhibit good mechanical and chemical properties, as well as excellent adhesion and thermal stability.

Social implications

The non-biodegradable PET has created environmental pollution problems connected to littering and illegal landfilling. It has become necessary to pay greater attention to recycling PET bottles for obtaining valuable products.

Originality/value

This approach is different from the earlier reports, where PET was recycled to recover the raw materials.

Details

Pigment & Resin Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 15 March 2013

Z.H.Z. Abidin, K.M. Nasir, S.K.M. Jamari, N. Saidon, S.V. Lee, N.A. Halim and R. Yahya

The purpose of this work is to investigate the correlation characteristics in mechanical, thermal and optical properties of PMMA‐acrylic polyol polymer blends mixed with…

Abstract

Purpose

The purpose of this work is to investigate the correlation characteristics in mechanical, thermal and optical properties of PMMA‐acrylic polyol polymer blends mixed with lawsone natural dye for coating paint application.

Design/methodology/approach

Natural brownish dye colorant was extracted from Lawsonia Inermis leaves used as a dye colorant in this paint coating system by using ethanol as the solvent. Poly(methyl methacrylate) (PMMA), blended with acrylic polyol was used as the binder system. The ratio of PMMA to acrylic polyol was varied with PMMA dominance. The dye colorant was fixed at 10 wt percent.

Findings

The potential time measurement tests showed that the dye colorant paint system with 10 wt percent of acrylic polyol has the highest coating resistance against electrolyte penetration. The dye colorant paint system with 30 wt percent acrylic polyol performed better in mechanical tests such as cross‐hatch and impact resistance. The dye colorant paint system molecular crosslinks were analysed by using the fourier transform infrared spectroscopy (FTIR) and X‐ray diffraction spectroscopy.

Research limitations/implications

The ratio of lawsone dye colorant in the polymer blends is found limited to 10 percent. Increasing in the percentage of lawsone dye colorant will cause inhomogeneity in coating paint sample.

Originality/value

A new formulation of natural dye colorant paint system with 10 percent wt dye volume concentration of lawsone as pigment was obtained.

Details

Pigment & Resin Technology, vol. 42 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 15 March 2013

S. Ramis Rau, B. Vengadaesvaran, N.N. Naziron and A.K. Arof

The purpose of this paper is to improve the strength and adhesion properties of modified acrylic polyol resin using epoxy polyol resin (DEGBA).

Abstract

Purpose

The purpose of this paper is to improve the strength and adhesion properties of modified acrylic polyol resin using epoxy polyol resin (DEGBA).

Design/methodology/approach

The hybrid systems were prepared by blending acrylic resin with epoxy polyol resin (Diglycidyl Ether of Bisphenol‐A, DGEBA) and polyisocyanate resin as hardener in various weight ratios with xylene as a solvent. The samples were applied on the pre‐treated cold rolled mild steel panels. The mechanical property of the blend has been evaluated using rapid impact tester (Sheen 806/40) and adhesion tester (Sheen Cross‐Hatch 750). Intended panels were checked for cracks using Dino‐Lite and Pinhole detectors (Elcometer 270/4). Crossed panels were observed for damages using digital polarized microscope (Dino‐Lite, AM413ZT). The thermal properties were studied using thermal analysis system (TGA TA‐Q500, DSC TA‐Q200).

Findings

The modification of acrylic polyol resins using DGEBA showed significant improvement of toughness compared to pure acrylic polyol resins. The blending systems with 10 wt percent of DGEBA and 90 wt percent of acrylic resin showed good adhesion and impact resistance properties on mild steel substrate.

Research limitations/implications

The hybrid coating system has contributed to the basic conceptual understanding of the corrosion protection property, focusing mainly on recent research available.

Practical implications

The blending method provided a simple and practical solution to improve the toughness of acrylic polyol resins.

Originality/value

The method for enhanced toughness of cured acrylic was novel and functionality of coating critically depends on adhesion between the coatings and underlying metal substrate.

Details

Pigment & Resin Technology, vol. 42 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 30 August 2013

Gururaj N. Manvi and Ramanand N. Jagtap

The purpose of this work is to develop flexible as well as rigid polyurethane coating by using mixed polyol. It is developed by using low cost reactant such as polyether…

Abstract

Purpose

The purpose of this work is to develop flexible as well as rigid polyurethane coating by using mixed polyol. It is developed by using low cost reactant such as polyether and introducing branching in it.

Design/methodology/approach

Radiation curable branched polyurethanes were synthesised. In this work, branched polyol was synthesised by using trimethylol propane (TMP) and reacted with adipic acid (AA), neopentyl glycol (NPG) (polyester) and polypropylene glycol (PPG) (polyether). These branched polyols were developed by varying ratio of polyether to polyester from 20:80, 40:60 and 55:45. These branched polyols were further reacted with isophorane di isocyanate (IPDI) and hydroxy ethyl metha acrylate (HEMA) to get vinyl terminated prepolymer.

Findings

The branched polyol due to presence of polyether offers excellent flexibility and polyester which provides excellent scratch, adhesion, and tensile strength. Use of reactive diluents is avoided, and its role is compensated by polyether in all systems, which takes care of reducing viscosity and improves flow and levelling properties.

Practical implications

Synthesis of branched polyol using polyesters and polyethers is more beneficial as it offers advantage of its combined property.

Originality/value

The polyurethane acrylate due to its polyol combination, branching and cross linking offers enhanced coating properties and can be used for various coating applications.

Details

Pigment & Resin Technology, vol. 42 no. 5
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 12 August 2019

Junrui Zhang, Guojun Jiang, Tianhao Huang, Jun Xie and Da Shi

The paper aims to provide a facile approach to the synthesis of polyurethane–silica nanocomposites by introducing self-made aqueous silica sols with different particle…

Abstract

Purpose

The paper aims to provide a facile approach to the synthesis of polyurethane–silica nanocomposites by introducing self-made aqueous silica sols with different particle sizes into polyurethane materials. This paper investigates the effects of the silica nanoparticles on the polyester polyol, as well as the physical properties and transmittance of the hybrid polyurethane coatings.

Design/methodology/approach

Colloidal silica particles of different sizes were obtained using a sol–gel process and were then embedded into polyester polyol by in-situ polymerization. These polyester polyol–silica resins were synthesized using an azeotrope process, using xylene to remove the water generated in the system and present in the dispersion medium for the colloidal silica. The polyester polyol–silica resins were further cured using isocyanate trimers to form polyurethane–silica hybrid films.

Findings

The paper observed that the viscosity of the polyester polyol–silica nanocomposite resins increased and their appearance changed from transparent to ivory white as the particle size of the added silica was increased. It was found that increasing the hydroxyl content of the silica improved the film transmittance in the visible light region. However, the transmittance decreased sharply once the diameter of the silica particles reached 100 nm.

Research limitations/implications

Because of the limitation of experimental conditions, some performances have not been tested. Therefore, researchers are encouraged to conduct further tests.

Practical implications

The paper provides a method of preparing hybrid polyurethane film by using silica; the results indicate that the introduction of nano-silica can improve the wear resistance and glass transition temperature of polyurethane coatings.

Originality/value

The results obtained in this study will be extremely useful to enhance the understanding of organic–inorganic hybrid materials.

Details

Pigment & Resin Technology, vol. 48 no. 5
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 7 September 2012

Pallavi P. Deshmukh, Prakash A. Mahanwar and Sunil S. Sabharwal

Urethane Acrylate Oligomer with 100% solids was synthesised and characterised in order to study the application in electron beam curing with varying ratio of Trimethylol…

Abstract

Purpose

Urethane Acrylate Oligomer with 100% solids was synthesised and characterised in order to study the application in electron beam curing with varying ratio of Trimethylol propane triacrylate (TMPTA). The purpose of this paper is to study effect of TMPTA addition on the crosslink density and different coating properties.

Design/methodology/approach

Polyester polyol was synthesised by reacting single diacid, adipic acid (AA), with Pentaerythritol (PENTA) and 1,6‐hexanediol (HD). Further, Urethane acrylate resin was synthesised by using Isophorone diisocyanate (IPDI), hydroxy ethyl acrylate (HEA) and Polyester polyol. The polyester polyol and urethane acrylate oligomer were characterised by 1H NMR, 13C NMR, FTIR and GPC. Further, TMPTA was added as a crosslinker to the urethane acrylate oligomer and cured by electron beam radiation. The cured UA films having varying concentration of TMPTA were employed to evaluate thermal property, contact angle analysis, mechanical and chemical properties.

Findings

The obtained results showed improvement in their chemical properties, mechanical properties, thermal properties and water contact angle at 20% of TMPTA iconcentration. The TMPTA also reduced the dose required for the curing.

Research limitations/implications

The resin can be synthesised from different isocyanates as TDI, MDI and HMDI, etc. The study can also be done with different multi or mono functional monomers such as methacrylate, hexanediol diacrylate, ethylene glycol diacrylate, etc.

Practical implications

The paper provides the better solution to reduce the cost of the electron beam radiation required for the curing.

Social implications

The method presented in the paper could be very useful for controlling environmental pollution; as the conventional method of curing releases volatile organic compounds (VOC).

Originality/value

In this paper, urethane acrylate and TMTPA cured with electron beam are shown to offer good coating properties. A high‐solid urethane acrylate coating would find numerous industrial applications in surface coatings.

Details

Pigment & Resin Technology, vol. 41 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

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