Temperature Stable Memory Foams

Patent Title: VISCOELASTIC POLYURETHANE FOAMS WITH REDUCED TEMPERATURE SENSITIVITY

 Number/Link: WO2018/169833

Applicant/Assignee:  Covestro

Publication date: 20 September 2018

Gist”: A polyol blend comprising a relatively low-EO monol,  diol and triol is foamed with TDI

Why it is interesting: Viscoelastic or “memory” foams are popular materials for pillows and mattresses. One drawback of these materials is the sensitivity of hardness to room temperature variations. According to this invention the hardness variations can be reduced by preparing the foams form TDI and a polyol blend comprising a monofuntional polyether with an EO content of less than 20%, a polyether diol and a polyether triol both with an EO content of less than 45% together with water, catalysts and other additives. The polyol blend can optionally be made in situ.  The foams show an E'(15°C)/E'(30°C) ratio between 1 and 4, a Tg of less than 20°C (defined as the temperature of max. tanδ),  together with high air flow and tear strength values.

DMTA

DMTA trace of foam according to the invention

UV Resistant Viscoelastic Foams

Patent Title: POLYURETHANE PRODUCT WITH SULFUR-CONTAINING POLYOL

 Number/Link: WO2018/111806

Applicant/Assignee:  Dow

Publication date: 21 June 2018

Gist”: VE foams using S-containing polyether polyols

Why it is interesting: According to this invention sulfur containing polyols improve the UV resistance of polyurethane materials.  It is believed that sulfur acts as a UV absorber incorporated into the polymer, thereby reducing the need for additives such as antioxidants.  In the examples an S-containing polyether diol is prepared by reacting 2,2′-thiodiethanol with propyleneoxide up to an OH value of  188 mg KOH/g. The diol is then used in an amount of 5 to 15% on the total polyol blend to prepare low resilience flexible foams showing an improved UV resistance.

 

TDE

2,2′-thiodiethanol

 

PCM-Containing Viscoelastic Foams

Patent Title: VISCOELASTIC POLYURETHANE FOAM WITH COATING

Number/Link: WO2017/210439

Applicant/Assignee: Dow

Publication date: 7 December 2017

“Gist”: Open-celled visco-foam is impregnated with an aqueous dispersant composition containing a phase change material

Why it is interesting: According to Dow, open-celled viscoelastic polyurethane foams can be prepared by using a acid-modified polyolefin latex cellopener, as discussed before in this blog. In the current invention these open-celled foams are impregnated with an aqueous composition comprising an ionomer (a sodium salt of a maleic anhydride copolymer) and a microencapsulated PCM. The composition is said to ‘coat’ the cell struts with PCM and increase the comfort properties of the foam.
I wonder if with this process enough PCM can be in introduced to have a noticeable effect.

bluewave

Dow’s proprietary BLUEWAVE dispersion process is used to prepare the cellopening latex

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

Cell structure of a reticulated foam

Green Tea Memory Foam

Patent Title: Foam with Green Tea Additive for Foam Mattresses, Pillows and Cushions

 Number/Link: US2016/0270549

Applicant/Assignee: Zinus

Publication date: 22-09-2016

Gist”: Green Tea is added to memory foam formulation

Why it is interesting: Powdered leaves of the Green Tea plant (Camellia sinensis) are added to memory foam formulations in an amount of less than 2% (w/w) on the total composition.  The Green Tea is said to kill bacteria, mites and molds and reduce the smell of the foam when used in pillows and mattresses for example. Since tea leaves are also claimed to “brighten eyesight, refresh the brain and resist radiation” it’s hard to know if the claim is true. If it doesn’t work it won’t hurt I guess.

Cammelia sinensis (Wikipedia)

Camellia sinensis (Wikipedia)