초록 ▼

A process for blowing a balloon from a tubular parison of a thermoplastic polymer material by radially expanding the parison at an elevated temperature and pressure, the process characterized in that: a) the polymer material includes a "H-bonding" polymer which undergoes interchain hydrogen bondi

A process for blowing a balloon from a tubular parison of a thermoplastic polymer material by radially expanding the parison at an elevated temperature and pressure, the process characterized in that: a) the polymer material includes a "H-bonding" polymer which undergoes interchain hydrogen bonding between at least some segments thereof; b) the parison is conditioned in a high moisture environment prior to blowing, and c) the balloon is blown after moisture conditioning of the parison and without an intervening drying thereof. H-bonding polymers may be polyamides, polyurethanes or block copolymers containing a polyamide or polyurethane block. The process reduces occurrence of fish eye defects in the formed balloons.

대표청구항 ▼

1. A process for blowing a balloon from a tubule parison of a thermoplastic polymer material by radially expanding the parison at an elevated temperature and pressure, the process characterized in that: a) the polymer material comprises a H-bonding polymer, the H-bonding polymer being a polymer w

1. A process for blowing a balloon from a tubule parison of a thermoplastic polymer material by radially expanding the parison at an elevated temperature and pressure, the process characterized in that: a) the polymer material comprises a H-bonding polymer, the H-bonding polymer being a polymer which undergoes interchain hydrogen bonding between at least some segments thereof; b) the prison is conditioned in a high moisture environment prior to blowing, wherein the high moisture environment is a high humidity atmosphere of at least 80% relative humidity at ambient temperature, and c) the balloon is blown after moisture conditioning of the parison and without an intervening drying thereof. 2. A process as in claim 1 wherein the balloon so formed is subsequently equilibrated at ambient relative humidity. 3. A process as in claim 1 wherein the high humidity atmosphere is at least 85% relative humidity at ambient temperature. 4. A process as in claim 3 wherein the high humidity atmosphere is at least 90% relative humidity at ambient temperature. 5. A process as in claim 1 wherein said H-bonding polymer is a polymer having N-H groups along at least a portion of the length of the polymer chain or on groups pendant thereto. 6. A process as in claim 1 wherein said H-bonding polymer is selected from the group consisting of polyamides, polyurethanes, and block copolymers containing polyamide or polyurethane segments. 7. A process as in claim 6 wherein said H-bonding polymer is a polyamide. 8. A process as in claim 7 wherein said polyamide is selected from the group consisting of nylon 6, nylon 6/6, nylon 6/10, nylon 6/12, nylon 9, nylon 11, nylon 12, polyamides prepared bypolycondensing xylylenediamine with an aliphatic dicarboxylic acid, and polyamides prepared by polycondensing isophthalic acid and an aliphatic diamine. 9. A process as in claim 6 wherein said H-bonding polymer is a polyurethane. 10. A process as in claim 6 wherein said H-bonding polymer is a block copolymer containing polyamide or polyurethane segments. 11. A process as in claim 10 the block copolymer is a polyamide-polyether-polyester. 12. A process as in claim 1 wherein the thermoplastic polymer material is a polymer blend comprising at least one said H-bonding polymer. 13. A process as in claim 1 wherein the parison is a multi-layer laminate at least one layer of which is composed of said H-bonding polymer. 14. A process as in claim 1 wherein the parison is conditioned for a time in excess of one hour which is sufficient to produce a moisture content growth rate which is 10% or less of the moisture content growth rate growth rate in the first hour of conditioning. 15. A process in claim 14 wherein said conditioning time is sufficient to produce a moisture content growth rate which is 5% or less of the moisture content growth rate growth rate in the first hour of conditioning. 16. A process as in claim 15 wherein the conditioning time is sufficient to produce a substantially equilibrated moisture content. 17. A process as in claim 1 wherein the parison is conditioned in said high moisture environment by soaking in liquid water.