FORM 2 THE PATENTS ACT, 1970
(39 of 1970) & The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION
Polyvinylformalethylal and Alkyl Phenol base Adhesive for airborne applications
2. APPLICANT(S)
(a) NAME: HINDUSTAN AERONAUTICS LIMITED
(b) NATIONALITY: INDIAN
(c) ADDRESS: AIRCRAFT UPGRADE R&D CENTRE, HAL, NASIK
3. PREAMBLE TO THE DESCRIPTION
PROVISIONAL The following I COMPLETE The following specification
specification describes the particularly describes the invention and the
invention. manner in which is to be performed.
x √

4. DESCRIPTION (Description shall start from next stage.) Refer Annexure I
5. CLAIMS (Not applicable for provisional specification. Claims should start with the preamble - "I/We claim" on separate page)
Refer Annexure II
6. DATE AND SIGNATURE (to be given at the end of last page of specification)
7. ABSTRACT OF THE INVENTION (to be given along with complete specification on separate page)
Refer Annexure III
Note :-
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* Strike out the column(s) which is/are not applicable.

Complete Specification of
Polyvinylformalethylal and Alkyl Phenol base Adhesive for airborne applications

1 Title of the Invention
Polyvinylformalethylal and Alkyl Phenol base Adhesive for airborne applicationsField of the Invention
2 Field of Invention
The invention relates to chemical engineering process in general and for Polyvinylformalethylal and Alkyl Phenol base adhesive composition in particular for use in industry, typically in aerospace industry.
3 Background of the Invention
During aircraft operation and exploitation frequent failure of parts made from material like steel, duralumin, foam materials, heat resisting foam plastics, glass textoliteetc and manufactured on the base of glass fabric impregnated parts due to harsh environmental conditions. These could lead to malfunctioning of parts leading to failure of system resulting in mission failure, or even loss of aircraft. Hence there was urgent need to evolve an effective adhesive mainly for steel parts.
4 Brief Summary of the Invention
The present invention relates to development of Polyvinylformalethylal and Alkyl Phenol baseAdhesive,used for gluing of parts made from material e.g. steel, duralumin, thermostable foam plastic, glass textolite and materials of honey comb structure, glass cloth of an aircraft. The formulation of ingredients in specific ratio and process for manufacturing of invented adhesive were carried out by various experiments to meet the desired properties within desire band with best results of the product to fulfil the functional requirement of the adhesive and to use the same for aircraft application. After manufacturing the adhesive, it was evaluated by testing for physico-mechanical properties as per aircraft requirement. It

offers highly improved properties at an appreciably low cost and fulfill the requirement of nation.
5 Detail Description of the Drawings
The formulation of ingredients is shown in flow chart shown in figure-1. Weight the chemicals as per the batch size , charge alkyl phenol base and polyvinlyformalethyal base resin in to the container. Weigh solvent Methyl Ethyl Keton and ethyl acetate in the container, stir all the ingredients till homogeneous solution is formed for approximately 4-5 hours.
6 Detail Description of the Invention
The formulation of ingredients in specific ratio and process for manufacturing of invented adhesive composition contains the following ingredients:-
- Alkyl phenol base and Polyvinylformalethylal base resins are used for manufacturing of adhesive;
- Catalyst is used to increase rate of reaction of chemicals;
- Hardner is used to control the curing reaction of the chemicals;
- Solvent, Methyl Ethyl Ketone (MEK) and Ethyl Acetate are used as
solvents to make the solution soluble and manufacture the final
product of the adhesive.
Polyvinylformalethylal and Alkyl Phenol base adhesive is manufactured using following ingredients:
Table -1

SI. No. Ingredient Nomenclature Qty. parts by weight in % Typically Qty in gm.
1. Alkyl phenol base resin 11-17 100
2. Polyvinylformalethylal base resin 11-17 100
3. Catalyst 0.2-0.3 2

SI. No. Ingredient Nomenclature Qty. parts by weight in % Typically Qty in gm.
4. Solvent, Methyl Ethyl Ketone (MEK) 19-29 170
5. Solvent, Ethyl Acetate 38-57 340
6. Hardner 0.4 - 0.7 4
Polyvinylformalethylal and Alkyl Phenol base adhesive is manufactured by mixing ingredients mentioned in the Table 1, stated , above by following process:
- Alkyl phenol base resin and Polyvinylformalethylal base resin are transferred to a stainless steel container.
- Solvents, Methyl Ethyl Ketone (MEK) and ethyl acetate are added into stainless steel container and are stirred till homogeneous solution is formed for approximately 4-5 hours.
- Catalyst and hardener are added in to the above mixture and stirred till homogeneity gained.
- The prepared adhesive is stored in container and tested for parameters for further end use application on an aircraft.
The various test performed and its results are given below:
Table - 2

Sr. No. Test Carried Out Result
1 Appearance Transparent, homogenous
liquid of colour ranging
from white to dark brown
2 Concentration, Dry residue, % 20 to 30
3 Viscosity by viscometer 50 to 120

Sr. No.
Test Carried Out Result
4 Shear strength between low alloys steels, Kg/cm2 at temp., minimum:
20 °C 150
200 °C 60
300 °C 35

Title Poiyvinylformalethylal and Alkyl Phenol base Adhesive for
Airborne applications Claims
We Claim,
1. A process for manufacturing of adhesive for use on aircraft to achieve Poiyvinylformalethylal and Alkyl Phenol base adhesive which is used for gluing of parts made from material e.g. steel, duralumin, foam materials, heat resisting foam plastics, glass textolite which are manufactured on the base of glass fabric impregnated with phenol formaldehyde resin between themselves and in combination with the articles which work at high temperature i.e. up to 300°C on an aircraft, and the product obtained thereof, comprising :
- a base chemicals, particularly in this case; Alkyl phenol base resin, (11 to 17 percent of total weight of final mixture) and Poiyvinylformalethylal base resin (11 to 17 percent of total weight of final mixture) resin are used as base resin for manufacturing of adhesive;
- a catalyst (0.2-0.3 percent of total weight of final mixture) is used to increase rate of reaction of chemicals;
- a hardner (0.4-0.7 percent of total weight of final mixture) is used to control the curing reaction of the chemicals;
- the solvents, Methyl Ethyl Ketone (MEK) (19 to 29 percent of total weight of final mixture) and ethyl acetate (38 to 57 percent of total weight of final mixture) are used to make the solution soluble and manufacture the final product of the adhesive;

- the solvent is adjusted to achieve dry residue 20 to 30 % for the adhesive.