All posts tagged hydrophobic

TPU with Moisture-Controlled Flexibility

Title: THERMOPLASTIC POLYURETHANE MATERIALS FOR FORMING MEDICAL DEVICES

Number/Link: WO2017/066381

Applicant/Assignee: Becton Dickinson

Publication Date: 20 april 2017

“Gist”: High hardblock TPU, based on side-chain branched chain extenders, softens in water

Why it is interesting: The invention is related to thermoplastic polyurethanes for medical applications especially for intravenous catheters. These catheters need to have a high stiffness when inserted but need to become flexible once in place to prevent injuries. This is accomplished with TPUs based on MDI, PTMEG and either 2,2-dimethyl-1,3-propanediol (neopentylglycol) or 2-methyl-1,3-propanediol (MPdiol) and having a hardblock content of 50 to 75%. The examples show indeed an increased stiffness at ambient conditions and a larger softening when soaked in saline solution compared to TPU produced with a linear chain extender. It is however not mentioned which linear chain extender was used.

Neopentylglycol

TPU-Silicone TPVs

Patent Title: THERMOPLASTIC POLYURETHANE COMPOSITE MATERIAL COMPOSITION, THERMOPLASTIC POLYURETHANE COMPOSITE MATERIAL AND MANUFACTURING METHOD THEREOF, SHOE MATERIAL AND WEARABLE APPARATUS

Number/Link: US2017 /0015825

Applicant/Assignee: Evermore Chem. Ind.

Publication date: 19-jan-2017

“Gist”: A blend of TPU and unsaturated silicone gum is dynamically vulcanized

Why it is interesting: A thermoplastic polyurethane is blended (in a kneader) with 1 to 5% w/w of double-unsaturated silicone rubber gum. The blend is then dynamically vulcanized by extruding (and pelletizing) it together with a peroxide curing agent like e.g. 1,3-bis-(t-butylperoxyisopropyl)benzene. The resulting thermoplastic is said to have improved slip resistance without reducing the TPU properties like abrasion resitance and is therefore said to be especially useful for the production of shoe-soles. It is ‘contemplated’ that the resulting material is a semi-IPN, but (i.m.o.) it is more likely that a seperate crosslinked silicone phase -and therefore a thermoplastic vulcanizate (TPV)- is formed.

1,3-bis-(t-butylperoxyisopropyl)benzene

In Situ Reticulated Viscoelastic Foams

Patent Title: VISCOELASTIC AND RETICULATED POLYURETHANE FOAM AND THE PREPARATION THEREOF

Number/Link: WO2016/198433

Applicant/Assignee: Covestro

Publication date: 15-dec-2016

“Gist”: Composition of 3 semi-miscible polyols and a surfactant

Why it is interesting: This case claims a polyol composition for the preparation of a viscoelastic, reticulated foam without the need for a separate reticulation step. The composition consists of (at least) three polyols and a surfactant: a low mole-weight all-PO ‘rigid’ triol, a conventional flexible polyol, a high- or all-EO polyol and some off-the-shelf silicone surfactant. The composition is foamed with water and polymeric MDI or a polymeric MDI/TDI mixture. This is a well-known composition and it is hard to see why this should result in a reticulated foam – unless maybe in some fine-tuned cases. Apart from the ball rebound being less than 15% the claims do not mention any parameters related to reticulated foam (such as airflow). It is doubtful (in my opinion) that this will get granted.

Cell structure of a reticulated foam

Innovation in Polyurethanes

All posts tagged hydrophobic

TPU with Moisture-Controlled Flexibility

TPU-Silicone TPVs

In Situ Reticulated Viscoelastic Foams

Pages

Categories

Search

Follow this blog via email

Follow Innovation in PU on Twitter