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Phenol modified DCO Alkyd (Silkyd 110 & 115) (Technical Note: ST 16)

Phenol Resin Modified Alkyd

Comparative Film Properties

DCO modified phenolic varnishes

Comparative Film Properties

Compatibility

Solubility

Mode of Supply

Recommended Driers

Recommended Applications

Typical Formulations

Technical Service

DCO modified phenolic varnishes (Silac V10D, Silac V20D)

1.0  Phenol Resin Modified Alkyd

 

(Silkyd 110 and Silkyd 115)

The Rosinated Alkyds are very popular in the Paint Industry. They were introduced primarily to reduce the cost of the Alkyd and to improve the drying time. But these advantages are gained at the cost of sharp deterioration of the properties of the original Alkyd, particularly its chemical and water resistance and out door durability. Even the cost advantage is not applicable now as the price of Rosin is comparable with that of Alkyds.

Modification with Styrene or Acrylic materials improves the film properties but the cost of the Alkyd goes up prohibitively for most of the applications.

Keeping these considerations inview we have developed Cardphenol and CNSL modified DCO Long oil Alkyds known as Silkyd 110 and Silkyd 115 respectively. Modified with Cardphenol or CNSL methylols reduce the drying time, improve the resistance to chemicals and water and outdoor durability, yet the cost is lower than the resonate Alkyd. The only disadvantage that these materials have is their pale colour and hence they can not be used for pure whites, but slightly off white paints such as the so called Hospital White are possible especially with Silkyd 110 being of lighter colour.

TopThe Cardphenol or CNSL resins are reacted with Alkyd and have both ester and ether linkages in the structure. They exhibit outstanding water, alkali and chemical resistance combined with excellent weather resistance particularly because the modifying methylol is based on phenol. The C 15 aliphatic chain further improves the flexibility and water resistance of the resultant polymer.

They are clear transparent and comparatively pale resins and are uniquely suitable as base for formulations of synthetic enamels of superior quality with improved chemical and mar resistance and outdoor durability.

They can replace with advantage of the Rosinated and pure Alkyds for all off white compositions and even Styrenated and, Acrylated Alkyds for some specific applications.

1.1 The comparative film properties of Silkyd 110 and 115 with pure and rosinated Alkyds are given over leaf.

Top2.0 Comparative Film Properties

 

The film properties of Silkyd 110 and Silkyd 115 made into 30% Solids in MTO with recommended driers are compared with those of pure long oil Alkyd (66%) and rosinated Alkyd varnish of same solid contents.

Film Properties

Silkyd 110

Silkyd 115

66% oil length Alkyd varnish

Rosinated Alkyd

Colour

Pale

Pale Red

Very light pale

Light Pale

Hard dry time (tack free)

3 to 3½  hours

3½ hours

4 to 6 hours

4 to 5 hours

Appearance

Highly glossy

Glossy

Highly Glossy

Highly Glossy

Scratch Hardness

1100 gms

1000 gms

600 gms

800 gms

Adhesion

Good

Good

Good

Satisfactory

Flexibility

Good

Good

Better

Good

Resistance to

    

water

NE (100)

NE (100)

SB (8)

NE (100)

Sodium Carbonate 5%

NE (75)

NE (75)

SB (25)

SB (25)

Sulphuric Acid 2%

NE (100)

NE (100)

SB (48)

SB (8)

White Spirit

NE (100)

NE (100)

NE (100)

SB (50)

Linseed Oil

NE (100)

NE (100)

SB (100)

SB (100)

Out door weathering

Good

Good

Excellent

Fair

Corrosion Resistance

Excellent

Excellent

Fair

Fair

Abbreviation: NE – No effect, SB – Slight blushing, SE – Slight effect.

( ) Figures within brackets indicate the number of hours tested.

Top3.0  DCO modified phenolic varnishes

 

Silac V 10D Silac V 20D – They are phenolic Varnishes in which phenolic component, CNSL/Cardphenol aldehyde is modified with a Conjugated oil such as DCO. The C 15 H 27 group of phenol methylol reacts with the residual OH group in DCO leading to a Complex molecular structure which imparts better resistance against water and chemicals. They have higher exterior durability in addition to better adhesion and flexibility.

Top4.0  Comparative Film Properties

 

The film properties of Silac V 10D and V 20 D are compared with those of Rosinated Alkyd after making them into a Varnish with 30% Solids and adding the recommended driers. The Viscosity is measured with 45% Solid Varnish in MTO in all the three cases.

Film Properties

Silac V 10D

Silac V 20D

Rosinated Alkyd Varnish

Colour

Reddish Yellow

Golden Yellow

Light pale

Hard dry (tack free)

4 hours

4 hours

5 hours

Appearance

Glossy

Highly glossy

Highly glossy

Scratch Hardness

900 gms

1000 gms

800 gms

Adhesion

Good

Good

Satisfactory

Viscosity (45% Solids)

225 to 350 Secs.

225 to 350 Secs.

200 to 300 Secs.

Resistance to water

NE (100)

NE (100)

SB (100)

Sodium Carbonate 5%

NE (60)

NE (60)

SB (10)

Sulphuric Acid 2%

NE (100)

NE (100)

SB (25)

Out door weathering

Good

Good

Fair

Abbreviation: NE – No effect, SB – Slight blushing, SE – Slight effect.

( ) Figures within brackets indicate the number of hours tested.

Top5.0  Compatibility

 

All the four products are compatible with drying oils, epoxies, estergums, phenolics and maleics, and to a limited extent with chlorinated resins. They are not compatible with urea.

Top6.0  Solubility

 

They are soluble in all proportions in MTO and other paint solvents such as Xylene, Napthas, Ketones etc.
  

Top7.0  Mode of Supply

 

They are supplied in 200 Kg/Ltr and 20 Kg/Ltr packing.

Top8.0  Recommended Driers

 

Drier combination such as 1% lead, 0.1% Cobalt, 0.2% Manganese metals on solid contents is recommended.

Top9.0  Recommended Applications

 

Off white Paints and Enamels

Insulating Varnishes

Redoxide Zinc Chrome Primers

Wood can Lacquers

Wood Finishes

Bobbin Paints

Aluminium Medium

Outdoor decorative Paints.

Top10.0  Typical Formulations

 

The following compositions can be regarded as suggestive only to illustrate the applications of this very versatile and popular resin. Silac V 10D and Silac V 20D can also be used if lower scratch hardness and longer drying time are acceptable. Allowance will have to be made for the lower solid content in this case.

10.1 High Gloss Enamel – Hospital White:

 

Titanium dioxide

100 parts by weight

White extender

10 parts by weight

Aluminium Stearate

6 parts by weight

Silkyd 110 (65%)

860 parts by weight

Antiskinning Agent (Ethylmethyl Ketoxime)

0.13 parts by weight

Add driers and the solvent as required.

10.2 High Gloss Enamel – Post office Red:

 

Silkyd 115 (65%)

45 part by weight

Hansa Red

2.2 parts by weight

Red Oxide

0.1 part by weight

China Clay

3.0 parts by weight

Whiting

2.0 parts by weight

Barytes

0.5 part by weight

Anti settling agent

0.3 parts by weight

Top

Add solvent and the driers as required.

10.3 High Gloss Enamels – Dark Smoke Gary

 

Titanium Dioxide

18.0 parts by weight

Whiting

4.7 parts by weight

Carbon black

1.5 parts by weight

Marine Blue

0.6 parts by weight

Silkyd 110 (65%)

154.0 parts by weight

Antiskinning agent

0.4 parts by weight

Top

Add solvent and the driers as required.

10.4 Anti Corrosive Primer:

Basic lead sulphate

20.0 parts by weight

Standard Aluminium Paste (66%)

10.0 parts by weight

Iron Oxide

10.0 parts by weight

Barytes

10.0 parts by weight

Silkyd 110 (65%) or 115 (65%)

58.0 parts by weight

MTO

5.0 parts by weight

Naptha

8.0 parts by weight

Add more solvent if required and the driers as recommended.

Top10.5 Insulating Varnish

 

Silkyd 110 (65%) or 115 (65%)

100 parts by weight

Ester Gum

30 parts by weight

Heat upto 100°C

15 to 20 minutes

Thin down with xylene/MTO (1:1)

50 parts by weight

Add usual driers as required.

In case body is required add a Hydrocarbon resin 20 to 50 parts by weight or ester gum, maleic resin and process.

10.6 Aluminium Paint: (dual pack leafing)

 

Silkyd 110 (65%)

8.3 parts by weight

MTO

9.7 parts by weight

Silicone Surfactant

0.1% parts by weight

Add driers as required.

Leafing Aluminium paste required as per IS specifications separately packed.

Top11.0 Technical Service

 

The Service of our well equipped Application Laboratory and technically qualified staff are at your disposal to provide further technical information and suggestions in regard to the applications of these Varnishes.

Caution: Because we cannot anticipate the conditions under which our products may be used, we do not guarantee the applicability or the accuracy of the above information. Users should make their own tests to determine the suitability of our products for their particular purpose. The products are sold without any such warranty either by express or implied. Moreover, the above information is not intended as recommendation to use our product in the infringement of any patent. Top