Classifications

• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B39/00—Hollow non-inflatable balls, i.e. having no valves
• • A—HUMAN NECESSITIES
  • A63—SPORTS; GAMES; AMUSEMENTS
  • A63B—APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT
  • A63B39/00—Hollow non-inflatable balls, i.e. having no valves
  • A63B2039/003—Hollow non-inflatable balls, i.e. having no valves substantially hollow and pressureless

Definitions

• Hollow inflated sportsballs are well known and many superior sportsballs are made from ethylene-vinyl-acetate co-polymer (E.V.A.). No hollow uninflated sportsball has hitherto been made in E.V.A.
• the present invention is based on the surprising discovery that a hollow non-inflated sportsball can be made from E.V.A.
• a hollow non-inflated sportsball consisting of a shell formed from a foamed E.V.A.
• the invention also provides a method of manufacturing a hollow non-inflated sportsball comprising the steps of heating a measured quantity of finely ground E.V.A. to which has been preblended a small quantity of a blowing agent having a gas evolution substantially at the fusion temperature of the E.V.A. in a rotating mould until the material is distributed evenly throughout the mould, fused and cured, the mould then being cooled and opened to release the ball.
• the ball is then decorated and coated with a polyurethane flexible lacquer to increase its resistance to scuffing.
• the E.V.A. may comprise a blend of E.V.A. with pigments.
• sportsball is herein meant a ball in the size range eight to eleven inches in diameter (203 to 280 mm) which range includes inter alia the size 5 and size 4 rugby ball, the basket ball, the five-a-side and volley ball together with the football and netball. Diameter is taken to means in the case of a non-spherical ball the longest sectional chord through the ball.
• All these sportsballs have to possess specific properties of bounce, hitherto obtained by internal pressurization, and it is surprising that in accordance with the present invention the sportsball is not inflated yet possesses good bounce properties and is not susceptible to puncture.
• the shell has a wall thickness of at least i/30th of the said diameter of the ball. It is preferred to make the wall of the shell within the size range six to eight millimetres.
• the mix of the composition of the wall of the shell is preferred to be in the ranges set out below - 45 wt. % to 75 wt. % of A the remainder except for impurities and pigment if any being B.
• A is 28 wt. % of vinyl acetate melting indes 5.0 ground to 400 ⁇ remainder ethylene vinyl co-polymer and where B is i8 wt. % of vinyl acetate melting index 150 ground to 300 ⁇ remainder ethylene vinyl co-polymer.
• a blowing agent is added to the mix the agent being chosen to give gas evolution at the fusion temperature of the said composition said agent being provided in the mix at one hundredth part ⁇ 0.5% of the total weight of the mix.
• the heating of the mix and blowing agent is effected at a suitable temperature within limits of ⁇ 5°
• An eight and one half inch diameter (220 mm) split spherical mould was charged with a mix of 400 grammes of 50 wt. % of A the remainder plus impurities being B.
• A was 28 wt. % of vinyl acetate melting index 5.0 ground to 400 ⁇ remainder ethylene vinyl co-polymer and where B was 18 wt. % of vinyl acetate melting index 150 ground to 300 ⁇ remainder ethylene vinyl co-polymer to said mix was added 4.3 grammes of an activated formulated azodicarbonamide blowing agent.
• the mould was closed and clamped and whilst rotating in two orthogonal planes it was heated to approximately 270°C for some ten minutes by hot air.
• the foamed E.V.A. was fully cured after ten minutes and the rotating mould was cooled. At the completion of cooling the mould was opened and the ball removed.
• the ball was found to have a wall thickness of 0.275 inch (6.98 mm) and was decorated and coated with a polyurethane lacquer to increase its resistance to wear and scuffing.

Landscapes

• Health & Medical Sciences (AREA)
• General Health & Medical Sciences (AREA)
• Physical Education & Sports Medicine (AREA)
• Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
• Moulding By Coating Moulds (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=10516646

Family Applications (1)

Country Status (2)

Cited By (1)

Families Citing this family (2)

Citations (8)

• 1980
  • 1980-10-14 GB GB8033060A patent/GB2085885A/en not_active Withdrawn
• 1981
  • 1981-10-12 EP EP81304740A patent/EP0050029A1/de not_active Withdrawn

Patent Citations (8)

Non-Patent Citations (1)

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