BACKGROUND

1. Field of the Invention

This disclosure relates to polymer resins and interlayers, in particular, to polymer resins suitable for use in polymer interlayers, including those utilized in multiple layer panels.

2. Description of Related Art

Poly(vinyl butyral) (PVB) is often used in the manufacture of polymer sheets that can be used as interlayers in multiple layer panels, including, for example, light-transmitting laminates such as safety glass or polymeric laminates. PVB is also used in photovoltaic solar panels to encapsulate the panels which are used to generate and supply electricity for commercial and residential applications.

Safety glass generally refers to a transparent laminate that includes at least one polymer sheet, or interlayer, disposed between two sheets of glass or other rigid substrate. Safety glass is often used as a transparent barrier in architectural and automotive applications, and one of its primary functions is to absorb energy resulting from impact or a blow without allowing penetration of the object through the glass and to keep the glass bonded even when the applied force is sufficient to break the glass. This prevents dispersion of sharp glass shards, which minimizes injury and damage to people or objects within an enclosed area. Safety glass may also provide other benefits, such as a reduction in ultraviolet (UV) and/or infrared (IR) radiation, and it may also enhance the aesthetic appearance of window openings through addition of color, texture, and the like. Additionally, safety glass with desirable sound insulation properties has also been produced, which results in quieter internal spaces.

Poly(vinyl acetal) resins typically include acetate pendant groups, hydroxyl pendant groups, and aldehyde pendant groups, such as n-butyraldehyde groups for a PVB resin, that are present along the vinyl polymer backbone. Properties of poly(vinyl acetal) resins are determined, in part, by the type(s) and relative amount of hydroxyl, acetate, and aldehyde groups and/or by the type and amount of plasticizer added to the resin. Therefore, selection of certain resin compositions and combination of those resins with various types and amount of plasticizers can provide resin compositions, layers, and interlayers having different properties.

However, such selections can have various drawbacks. For example, PVB resin compositions having high residual hydroxyl contents and low plasticizer contents tend to have higher glass transition temperatures, which make such resins desirable in safety performance applications. However, these resins exhibit very poor vibration dampening and sound attenuation performance. Similarly, PVB resin compositions having lower residual hydroxyl contents and higher amounts of plasticizer may exhibit good vibration and sound dampening properties, but typically have limited, if any, impact resistance over a broad temperature range.

Thus, a need exists for polymer resins that exhibit multiple desirable properties and that have mechanical, optical, and/or acoustic properties that can be adjusted as needed so that the resin can be utilized in a wide variety of applications. Additionally, a need exists for resin compositions, layers, and interlayers including such resins, which can be employed in several end uses, including in safety glass, structural applications and as polymeric laminates.

SUMMARY

One embodiment of the present invention concerns an interlayer comprising: a resin layer comprising a poly(vinyl acetal) resin and a plasticizer, wherein the poly(vinyl acetal) resin has a residual hydroxyl content of at least 22 weight percent and comprises at least 10 weight percent of residues of at least one aldehyde other than n-butyraldehyde, based on the total weight of aldehyde residues of the poly(vinyl acetal) resin, and wherein the resin layer has a glass transition temperature greater than 45° C.

Another embodiment of the present invention concerns an interlayer comprising: a resin layer comprising: a poly(vinyl acetal) resin, wherein the poly(vinyl acetal) resin has a residual hydroxyl content of at least 24 weight percent and comprises at least 50 weight percent of residues of at least one aldehyde other than n-butyraldehyde, based on the total weight of aldehyde residues of the poly(vinyl acetal) resin, and from 5 to 30 phr of a plasticizer, and wherein the resin layer has a glass transition temperature greater than 45° C.

Yet another embodiment of the present invention concerns An interlayer comprising: a resin layer comprising: a poly(vinyl acetal) resin, wherein the poly(vinyl acetal) resin has a residual hydroxyl content of at least 24 weight percent and comprises at least 50 weight percent of residues of iso-butyraldehyde or pivaldehyde, based on the total weight of aldehyde residues of the poly(vinyl acetal) resin, and from 5 to 20 phr of a plasticizer, and wherein the resin layer has a glass transition temperature greater than 50° C.

Another embodiment of the invention concerns a multilayer glass panel comprising the interlayer of the invention.

Still another embodiment of the invention concerns a method of making the interlayer of the invention.

